Glossary of medical terms

From WikiMD

  • Abdominal cavity - the cavity containing the major viscera; in mammals it is separated from the thorax by the diaphragm
  • Abortion - termination of pregnancy; failure of a plan
  • Abscess - symptom consisting of a localized collection of pus surrounded by inflamed tissue
  • ACE inhibitor - antihypertensive drug that blocks the formation of angiotensin in the kidney, leading to relaxation of the arteries; promotes the excretion of salt and water by inhibiting the activity of the angiotensin converting enzyme; also used to treat congestive heart failure
  • Acidosis - abnormally high acidity (excess hydrogen ion concentration) of the blood and other body tissues
  • Acne - an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones
  • Acquired - gotten through environmental forces
  • Acute - having or experiencing a rapid onset and short but severe course; of critical importance and consequence; extremely sharp or intense; having or demonstrating ability to recognize or draw fine distinctions; of an angle; less than 90 degrees; ending in a sharp point;  a mark (') placed above a vowel to indicate pronunciation
  • Addiction - (Roman law) a formal award by a magistrate of a thing or person to another person (as the award of a debtor to his creditor); a surrender to a master; an abnormally strong craving; being abnormally tolerant to and dependent on something that is psychologically or physically habit forming (especially alcohol or narcotic drugs)
  • Adenitis - inflammation of a gland or lymph node
  • Adipose tissue - a kind of body tissue containing stored fat that serves as a source of energy; it also cushions and insulates vital organs
  • Affective disorder - any mental disorder not caused by detectable organic abnormalities of the brain and in which a major disturbance of emotions is predominant
  • Afterbirth - the placenta and fetal membranes that are expelled from the uterus after the baby is born
  • Afterpains - pains felt by a woman after her baby is born; associated with contractions of the uterus
  • AIDS - a serious (often fatal) disease of the immune system transmitted through blood products especially by sexual contact or contaminated needles
  • Air embolism - obstruction of the circulatory system caused by an air bubble as, e.g., accidentally during surgery or hypodermic injection or as a complication from scuba diving; pain resulting from rapid change in pressure
  • Albinism - the congenital absence of pigmentation in the eyes and skin and hair
  • Alimentary canal - tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination
  • Alkalosis - abnormally high alkalinity (low hydrogen ion concentration) of the blood and other body tissues
  • Allergen - any substance that can cause an allergy
  • Allergy - hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity
  • Alopecia - loss of hair (especially on the head) or loss of wool or feathers; in humans it can result from heredity or hormonal imbalance or certain diseases or drugs and treatments (chemotherapy for cancer)
  • ALS - thickening of tissue in the motor tracts of the lateral columns and anterior horns of the spinal cord; results in progressive muscle atrophy that starts in the limbs
  • Altitude sickness - effects (as nosebleed or nausea) of oxygen deficiency in the blood and tissues at high altitudes
  • Amenorrhea - absence or suppression of normal menstrual flow
  • Amniocentesis - (pregnancy) extraction by centesis of amniotic fluid from a pregnant woman (after the 15th week of pregnancy) to aid in the diagnosis of fetal abnormalities
  • Amniotic fluid - the serous fluid in which the embryo is suspended inside the amnion
  • Amyotrophic lateral sclerosis - thickening of tissue in the motor tracts of the lateral columns and anterior horns of the spinal cord; results in progressive muscle atrophy that starts in the limbs
  • Anabolic steroid - any of a group of synthetic steroid hormones used to stimulate muscle and bone growth; more than 100 have been developed and each requires a prescription to be used legally in the United States; sometimes used illicitly by athletes to increase their strength
  • Analgesic - capable of relieving pain;  a medicine used to relieve pain
  • Anaphylactic shock - a severe and rapid and sometimes fatal hypersensitivity reaction to a substance (especially a vaccine or penicillin or shellfish or insect venom) to which the organism has become sensitized by previous exposure
  • Anatomy - a detailed analysis; the branch of morphology that deals with the structure of animals; alternative names for the body of a human being
  • Androgen - male sex hormone that is produced in the testes and responsible for typical male sexual characteristics
  • Anemia - genus of terrestrial or lithophytic ferns having pinnatifid fronds; chiefly of tropical America; a deficiency of red blood cells; a lack of vitality
  • Anencephaly - a defect in brain development resulting in small or missing brain hemispheres
  • Anesthesia - loss of bodily sensation with or without loss of consciousness
  • Anesthetic - characterized by insensibility;  a drug that causes temporary loss of bodily sensations
  • Aneurysm - a cardiovascular disease characterized by a saclike widening of an artery resulting from weakening of the artery wall
  • Angina pectoris - a heart condition marked by paroxysms of chest pain due to reduced oxygen to the heart
  • Angioma - a tumor consisting of a mass of blood or lymphatic vessels
  • Angioplasty - an operation to repair a damaged blood vessel or unblock a coronary artery
  • Anorexia nervosa - (psychiatry) a psychological disorder characterized by somatic delusions that you are too fat despite being emaciated
  • Antacid - acting to neutralize acid (especially in the stomach);  an agent that counteracts or neutralizes acidity (especially in the stomach)
  • Antibody - any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response
  • Antihistamine - a medicine used to treat allergies and hypersensitive reactions and colds; works by counteracting the effects of histamine on a receptor site
  • Anus - excretory opening at the end of the alimentary canal
  • Aorta - the large trunk artery that carries blood from the left ventricle of the heart to branch arteries
  • Apgar score - an assessment of the physical condition of a newborn infant; involves heart rate and muscle tone and respiratory effort and color and reflex responsiveness
  • Aplasia - failure of some tissue or organ to develop
  • Aplastic anemia - anemia characterized by pancytopenia resulting from failure of the bone marrow; can be caused by neoplasm or by toxic exposure
  • Apnea - transient cessation of respiration
  • Appendix - a vestigial process that extends from the lower end of the cecum and that resembles a small pouch; supplementary material that is collected and appended at the back of a book
  • ARC - a continuous portion of a circle; electrical conduction through a gas in an applied electric field; something curved in shape; verb form an arch or curve
  • Artery - a major thoroughfare that bears important traffic; a blood vessel that carries blood from the heart to the body
  • Arthritis - inflammation of a joint or joints
  • Arthroscopy - a minimally invasive operation to repair a damaged joint; the surgeon examines the joint with an arthroscope while making repairs through a small incision
  • Artificial insemination - the introduction of semen into the oviduct or uterus by some means other than sexual intercourse
  • ventilation - the act of supplying fresh air and getting rid of foul air; a mechanical system in a building that provides fresh air; the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation; free and open discussion of (or debate on) some question of public interest
  • Ascites - accumulation of serous fluid in peritoneal cavity
  • Ascorbic acid - a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy
  • Asphyxia - a condition in which insufficient or no oxygen and carbon dioxide are exchanged on a ventilatory basis; caused by choking or drowning or electric shock or poison gas
  • Asthma - respiratory disorder characterized by wheezing; usually of allergic origin
  • Astigmatism - (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point; (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea
  • Atheroma - a fatty deposit in the intima (inner lining) of an artery; can obstruct blood flow
  • Atherosclerosis - a stage of arteriosclerosis involving fatty deposits (atheromas) inside the arterial walls
  • Atresia - an abnormal condition in which a normal opening or tube in the body (as the urethra) is closed or absent
  • Atrophy - any weakening or degeneration (especially through lack of use); a decrease in size of an organ caused by disease or disuse; verb undergo atrophy
  • Audiogram - a graphical representation of a person's auditory sensitivity to sound
  • Aura - an indication of radiant light drawn around the head of a saint; a sensation (as of a cold breeze or bright light) that precedes the onset of certain disorders such as a migraine attack or epileptic seizure; a distinctive but intangible quality surrounding a person or thing
  • Auscultation - listening to sounds within the body (usually with a stethoscope)
  • Autism - (psychiatry) an abnormal absorption with the self; marked by communication disorders and short attention span and inability to treat others as people
  • Autoimmune disease - any of a large group of diseases characterized by abnormal functioning of the immune system that causes your immune system to produce antibodies against your own tissues
  • Autonomic nervous system - the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands
  • Autopsy - an examination and dissection of a dead body to determine cause of death or the changes produced by disease; verb perform an autopsy on a dead body; do a post mortem
  • Axilla - the hollow under the arm where it is joined to the shoulder
  • Bacillus - aerobic rod shaped spore producing bacterium; often occurring in chainlike formations; found primarily in soil
  • Bacteremia - transient presence of bacteria (or other microorganisms) in the blood
  • Bacterium - (microbiology) single celled or noncellular spherical or spiral or rod shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered plants
  • Barium enema - contrast medium is injected into the rectum and x rays are taken to search for lesions
  • B cell - a lymphocyte derived from bone marrow that provides humoral immunity; it recognizes free antigen molecules in solution and matures into plasma cells that secrete immunoglobulin (antibodies) that inactivate the antigens
  • Bends - pain resulting from rapid change in pressure
  • Beta blocker - any of various drugs used in treating hypertension or arrhythmia; decreases force and rate of heart contractions by blocking beta adrenergic receptors of the autonomic nervous system
  • Beta carotene - an isomer of carotene that is found in dark green and dark yellow fruits and vegetables
  • Bilateral - having two sides or parts; affecting or undertaken by two parties; having identical parts on each side of an axis
  • Bile - a digestive juice secreted by the liver and stored in the gallbladder; aids in the digestion of fats
  • Bile duct - a duct formed by the hepatic and cystic ducts; opens into the duodenum
  • Bilirubin - an orange yellow pigment in the bile that forms as a product of hemoglobin; excess amounts in the blood produce the yellow appearance observed in jaundice
  • Biochemistry - the organic chemistry of compounds and processes occuring in organisms; the effort to understand biology within the context of chemistry
  • Biofeedback - a training program in which a person is given information about physiological processes (heart rate or blood pressure) that is not normally available with the goal of gaining conscious control of them
  • Bipolar disorder - a mental disorder characterized by episodes of mania and depression
  • Birth canal - a passage in the uterus and vagina through which a fetus passes during vaginal birth
  • Birthmark - a blemish on the skin that is formed before birth
  • Bisexuality - sexual activity with both men and women; showing characteristics of both sexes
  • Bladder - a bag that fills with air; a distensible membranous sac (usually containing liquid or gas)
  • Blepharitis - inflammation of the eyelids characterized by redness and swelling and dried crusts
  • Blind spot - the point where the optic nerve enters the retina; not sensitive to light; a subject about which you are ignorant or prejudiced and fail to exercise good judgment
  • Blood clot - a semisolid mass of coagulated red and white blood cells
  • Blood poisoning - invasion of the bloodstream by virulent microorganisms from a focus of infection
  • Blood pressure - the pressure of the circulating blood against the walls of the blood vessels; results from the systole of the left ventricle of the heart; sometimes measured for a quick evaluation of a person's health
  • Blood type - human blood cells (usually just the red blood cells) that have the same antigens
  • B lymphocyte - a lymphocyte derived from bone marrow that provides humoral immunity; it recognizes free antigen molecules in solution and matures into plasma cells that secrete immunoglobulin (antibodies) that inactivate the antigens
  • Boil - a painful sore with a hard core filled with pus; the temperature at which a liquid boils at sea level; verb cook in boiling liquid; bring to, or maintain at, the boiling point; come to the boiling point and change from a liquid to vapor; be in an agitated emotional state; be agitated
  • Bone marrow - the fatty network of connective tissue that fills the cavities of bones; very tender and very nutritious tissue from marrowbones
  • Booster - an additional dose that makes sure the first dose was effective; the first stage of a multistage rocket; an amplifier for restoring the strength of a transmitted signal; a thief who steals goods that are in a store; someone who is an active supporter and advocate; a person who backs a politician or a team etc.
  • Botulism - food poisoning from ingesting botulin; not infectious; affects the CNS; can be fatal if not treated promptly
  • Bowel - the part of the alimentary canal between the stomach and the anus
  • Brain death - death when respiration and other reflexes are absent; consciousness is gone; organs can be removed for transplantation before the heartbeat stops
  • Breech birth - delivery of an infant whose feet or buttocks appear first
  • Bronchiolitis - inflammation of the membranes lining the bronchioles
  • Bronchitis - inflammation of the membranes lining the bronchial tubes
  • Bronchodilator - a drug that relaxes and dilates the bronchial passageways and improves the passages of air into the lungs
  • Bronchospasm - a spasm of the bronchi that makes exhalation difficult and noisy; associated with asthma and bronchitis
  • Bruise - an injury that doesn't break the skin but results in some discoloration; verb damage (plant tissue) by abrasion of pressure; break up into small pieces for food preparation; injure the underlying soft tissue of bone of; hurt the feelings of
  • Bruxism - involuntarily or unconsciously clenching or grinding the teeth, typically during sleep
  • Bubonic plague - the most common form of the plague in humans; characterized by chills, prostration, delirium and the formation of buboes in the armpits and groin; does not spread from person to person
  • Bulimia - pathologically insatiable hunger (especially when caused by brain lesions); a disorder of eating seen among young women who go on eating binges and then feel guilt and depression and self condemnation
  • Bunion - a painful swelling of the bursa of the first joint of the big toe
  • Bursa - a small fluid filled sac located between movable parts of the body especially at joints; a city in northwestern Turkey
  • Bursitis - inflammation of a bursa; frequently in the shoulder
  • Bypass - a road that takes traffic around the edge of a town; a surgically created shunt (usually around a damaged part); a conductor having low resistance in parallel with another device to divert a fraction of the current; verb avoid something unpleasant or laborious
  • Calcitonin - thyroid hormone that tends to lower the level of calcium in the blood plasma and inhibit resorption of bone
  • Calcium - a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
  • Callus - (botany) an isolated thickening of tissue, especially a stiff protuberance on the lip of an orchid; bony tissue formed during the healing of a fractured bone; an area of skin that is thick or hard from continual pressure or friction (as the sole of the foot); verb form a callus or calluses; cause a callus to form on
  • Calorie - unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure; a unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure; used by nutritionists to characterize the energy producing potential in food
  • Canal - long and narrow strip of water made for boats or for irrigation; (astronomy) an indistinct surface feature of Mars once thought to be a system of channels; they are now believed to be an optical illusion; a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance; verb provide (a city) with a canal
  • Cancer - type genus of the family Cancridae; the fourth sign of the zodiac; the sun is in this sign from about June 21 to July 22; a small zodiacal constellation in the northern hemisphere; between Leo and Gemini; (astrology) a person who is born while the sun is in Cancer; any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream
  • Candidiasis - an infection caused by fungi of the genus Monilia or Candida (especially Candida albicans)
  • Canker sore - an ulceration (especially of the lips or lining of the mouth)
  • Capillary - long and slender with a very small internal diameter; of or relating to hair;  a tube of small internal diameter; holds liquid by capillary action; any of the minute blood vessels connecting arterioles with venules
  • Carbohydrate - an essential structural component of living cells and source of energy for animals; includes simple sugars with small molecules as well as macromolecular substances; are classified according to the number of monosaccharide groups they contain
  • Carbon dioxide - a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis
  • Carcinoma - any malignant tumor derived from epithelial tissue; one of the four major types of cancer
  • Cardiac arrest - absence of systole; failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation) with consequent absence of the heart beat leading to oxygen lack and eventually to death
  • Cardiomyopathy - a disorder (usually of unknown origin) of the heart muscle (myocardium)
  • Cardiopulmonary resuscitation - an emergency procedure consisting of external cardiac massage and artificial respiration; the first treatment for a person who has collapsed and has no pulse and has stopped breathing; attempts to restore circulation of the blood and prevent death or brain damage due to lack of oxygen
  • Carotene - yellow or orange red fat soluble pigments in plants; an orange isomer of an unsaturated hydrocarbon found in many plants; is converted into vitamin A in the liver
  • Carpal tunnel syndrome - a painful disorder caused by compression of a nerve in the carpal tunnel; characterized by discomfort and weakness in the hands and fingers and by sensations of tingling, burning or numbness
  • Cartilage - tough elastic tissue; mostly converted to bone in adults
  • Cast - (of molten metal or glass) formed by pouring or pressing into a mold;  the act of throwing dice; object formed by a mold; bandage consisting of a firm covering (often made of plaster of Paris) that immobilizes broken bones while they heal; the actors in a play; the distinctive form in which a thing is made; a violent throw; the act of throwing a fishing line out over the water by means of a rod and reel; container into which liquid is poured to create a given shape when it hardens; the visual appearance of something or someone; verb form by pouring (e.g., wax or hot metal) into a cast or mold; select to play,sing, or dance a part in a play, movie, musical, opera, or ballet; deposit; assign the roles of (a movie or a play) to actors; eject the contents of the stomach through the mouth; formulate in a particular style or language; choose at random; throw forcefully; get rid of; put or send forth; move about aimlessly or without any destination, often in search of food or employment
  • Cataract - a large waterfall; violent rush of water over a precipice; clouding of the natural lens of the eye
  • Catheter - a thin flexible tube inserted into the body to permit introduction or withdrawal of fluids or to keep the passageway open
  • Cauterization - the act of coagulating blood and destroying tissue with a hot iron or caustic agent or by freezing
  • Cecum - the cavity in which the large intestine begins and into which the ileum opens
  • Cell - (biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals; a device that delivers an electric current as the result of a chemical reaction; a room where a prisoner is kept; small room is which a monk or nun lives; any small compartment; a small unit serving as part of or as the nucleus of a larger political movement; a hand held mobile radiotelephone for use in an area divided into small sections, each with its own short range transmitter/receiver
  • Cellulitis - an inflammation of body tissue (especially that below the skin) characterized by fever and swelling and redness and pain
  • Cerebellum - a major division of the vertebrate brain; situated above the medulla oblongata and beneath the cerebrum in humans
  • Cerebral palsy - a loss or deficiency of motor control with involuntary spasms caused by permanent brain damage present at birth
  • Cerebrospinal fluid - clear liquid produced in the ventricles of the brain; fills and protects cavities in the brain and spinal cord
  • Cerebrum - anterior portion of the brain consisting of two hemispheres; dominant part of the brain in humans
  • Cervical cap - a contraceptive device consisting of a small thimble shaped cup that is placed over the uterine cervix to prevent the entrance of spermatozoa
  • Cervical smear - a sample of secretions and superficial cells of the uterine cervix and uterus; examined with a microscope to detect any abnormal cells
  • Cervix - necklike opening to the uterus; the part of an organism that connects the head to the rest of the body
  • Cesarean section - the delivery of a fetus by surgical incision through the abdominal wall and uterus (from the belief that Julius Caesar was born that way)
  • Chancre - a small hard painless nodule at the site of entry of a pathogen (as syphilis)
  • Chemotherapy - the use of chemical agents to treat or control disease (or mental illness)
  • Chickenpox - an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body
  • Chlamydia - coccoid rickettsia infesting birds and mammals; cause infections of eyes and lungs and genitourinary tract; a sexually transmitted infection caused by bacteria of the genus Chlamydia
  • Cholecystectomy - surgical removal of the gall bladder (usually for relief of gallstone pain)
  • Cholera - an acute intestinal infection caused by ingestion of contaminated water or food
  • Cholesterol - an animal sterol that is normally synthesized by the liver; the most abundant steroid in animal tissues
  • Chondroma - a common benign tumor of cartilage cells
  • Chorionic villus sampling - a prenatal test to detect birth defects at an early stage of pregnancy; tissue from the chorionic villi is assayed
  • Chronic - being long lasting and recurrent or characterized by long suffering
  • Circumcision - the act of circumcising; surgical removal of the foreskin of males; the act of circumcising performed on males eight days after birth as a Jewish and Muslim religious rite; (Roman Catholic Church and Anglican Church) feast day celebrating the circumcision of Jesus; celebrated on January 1st
  • Cirrhosis of the liver - a chronic disease interfering with the normal functioning of the liver; the major cause is chronic alcoholism
  • Claudication - disability of walking due to crippling of the legs or feet
  • Clavicle - bone linking the scapula and sternum
  • Cleft lip - a congenital cleft in the middle of the upper lip
  • Clinical trial - a rigorously controlled test of a new drug or a new invasive medical device on human subjects; in the United States it is conducted under the direction of the FDA before being made available for general clinical use
  • Clitoris - a female sexual organ homologous to the penis
  • Clone - a group of genetically identical cells or organisms derived from a single cell or individual by some kind of asexual reproduction; an unauthorized copy or imitation; a person who is almost identical to another; verb make multiple identical copies of
  • Closed fracture - an uncomplicated fracture in which the broken bones to not pierce the skin
  • Clotting factor - any of the factors in the blood whose actions are essential for blood coagulation
  • Clubfoot - congenital deformity of the foot usually marked by a curled shape or twisted position of the ankle and heel and toes
  • Cluster headache - a painful recurring headache associated with the release of histamine from cells
  • CNS - the portion of the vertebrate nervous system consisting of the brain and spinal cord
  • Coagulation - the process of forming semisolid lumps in a liquid
  • Coccyx - the end of the vertebral column in humans and tailless apes
  • Cochlea - the snail shaped tube (in the inner ear coiled around the modiolus) where sound vibrations are converted into nerve impulses by the organ of Corti
  • Coitus - the act of sexual procreation between a man and a woman; the man's penis is inserted into the woman's vagina and excited until orgasm and ejaculation occur
  • Cold sore - caused by herpes simplex virus type 1 (HSV 1)
  • Colic - acute abdominal pain (especially in infants)
  • Colitis - inflammation of the colon
  • Colon - the part of the large intestine between the cecum and the rectum; it extracts moisture from food residues before they are excreted; a punctuation mark (:) used after a word introducing a series or an example or an explanation (or after the salutation of a business letter); a port city at the Caribbean entrance to the Panama Canal; the basic unit of money in Costa Rica; equal to 100 centimos; the basic unit of money in El Salvador; equal to 100 centavos
  • Colonoscopy - visual examination of the colon (with a colonoscope) from the cecum to the rectum; requires sedation
  • Colostomy - a surgical operation that creates an opening from the colon to the surface of the body to function as an anus
  • Coma - a state of deep and often prolonged unconsciousness; usually the result of disease or injury; (astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed; a usually terminal tuft of hairs especially on a seed
  • Common cold - a mild viral infection involving the nose and respiratory passages (but not the lungs)
  • Compound fracture - bone fracture associated with lacerated soft tissue or an open wound
  • Compression fracture - fracture in which the bone collapses (especially in short bones such as vertebrae)
  • Concussion - any violent blow; injury to the brain caused by a blow; usually resulting in loss of consciousness
  • Congenital - present at birth but not necessarily hereditary; acquired during fetal development
  • Conjunctiva - a transparent membrane covering the eyeball and under surface of the eyelid
  • Connective tissue - tissue of mesodermal origin consisting of e.g. collagen fibroblasts and fatty cells; supports organs and fills spaces between them and forms tendons and ligaments
  • Constipation - irregular and infrequent or difficult evacuation of the bowels; can be a symptom of intestinal obstruction or diverticulitis; the act of making something futile and useless (as by routine)
  • Contraindication - (medicine) a reason that makes it inadvisable to prescribe a particular drug or employ a particular procedure or treatment
  • Contusion - the action of bruising; an injury that doesn't break the skin but results in some discoloration
  • Corn - something sentimental or trite; ears of corn grown for human food; tall annual cereal grass bearing kernels on large ears: widely cultivated in America in many varieties; the principal cereal in Mexico and Central and South America since pre Columbian times; (Great Britain) any of various cereal plants (especially the dominant crop of the region wheat in England or oats in Scotland and Ireland); the dried grains or kernels or corn used as animal feed or ground for meal; a hard thickening of the skin (especially on the top or sides of the toes) caused by the pressure of ill fitting shoes; whiskey distilled from a mash of not less than 80 percent corn; verb preserve with salt; feed (cattle) with corn
  • Cornea - transparent anterior portion of the outer covering of the eye; it covers the lens and iris and is continuous with the sclera
  • Coronary - surrounding like a crown (especially of the blood vessels surrounding the heart);  obstruction of blood flow in a coronary artery by a blood clot (thrombus)
  • Coronary thrombosis - obstruction of blood flow in a coronary artery by a blood clot (thrombus)
  • Corpuscle - either of two types of cells (erythrocytes and leukocytes) and sometimes including platelets; (nontechnical usage) a tiny piece of anything
  • CPR - an emergency procedure consisting of external cardiac massage and artificial respiration; the first treatment for a person who has collapsed and has no pulse and has stopped breathing; attempts to restore circulation of the blood and prevent death or brain damage due to lack of oxygen
  • Croup - a disease of infants and young children; harsh coughing and hoarseness and fever and difficult breathing; the part of a quadruped that corresponds to the human buttocks
  • Culture - the raising of plants or animals; (biology) the growing of microorganisms in a nutrient medium (such as gelatin or agar); the tastes in art and manners that are favored by a social group; the attitudes and behavior that are characteristic of a particular social group or organization; a particular society at a particular time and place; all the knowledge and values shared by a society; a highly developed state of perfection; having a flawless or impeccable quality
  • Curettage - surgery to remove tissue or growths from a bodily cavity (as the uterus) by scraping with a curette
  • Cyanosis - a bluish discoloration of the skin and mucous membranes; a sign that oxygen in the blood is dangerously diminished (as in carbon monoxide poisoning)
  • Cyst - a closed sac that develops abnormally in some body structure; a small anatomically normal sac or bladderlike structure (especially one containing fluid)
  • Cystic fibrosis - the most common congenital disease; the child's lungs and intestines and pancreas become clogged with thick mucus; caused by defect in a single gene; there is no cure
  • D and C - a surgical procedure usually performed under local anesthesia in which the cervix is dilated and the endometrial lining of the uterus is scraped with a curet; performed to obtain tissue samples or to stop prolonged bleeding or to remove small tumors or to remove fragments of placenta after childbirth or as a method of abortion
  • Debridement - surgical removal of foreign material and dead tissue from a wound in order to prevent infection and promote healing
  • Defecation - the elimination of fecal waste through the anus
  • Defibrillation - treatment by stopping fibrillation of heart muscles (usually by electric shock delivered by a defibrillator)
  • Degenerative arthritis - chronic breakdown of cartilage in the joints; the most common form of arthritis occurring usually after middle age
  • Dehydration - the process of extracting moisture; depletion of bodily fluids; dryness resulting from the removal of water
  • Dementia - mental deterioration of organic or functional origin
  • Depilatory - able to remove hair or render hairless;  a cosmetic for temporary removal of undesired hair; a chemical (usually a sulfide) used to remove hair or wool or bristles from hides
  • Depression - pushing down; sad feelings of gloom and inadequacy; angular distance below the horizon (especially of a celestial object); a concavity in a surface produced by pressing; a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity; a long term economic state characterized by unemployment and low prices and low levels of trade and investment; a period during the 1930s when there was a worldwide economic depression and mass unemployment; a sunken or depressed geological formation; a state of depression and anhedonia so severe as to require clinical intervention; an air mass of lower pressure; often brings precipitation
  • Dermabrasion - removal of scars or tattoos by anesthetizing the skin surface and then sanding or scraping off some of the outer skin layer
  • Dermatitis - inflammation of the skin; skin becomes itchy and may develop blisters
  • Dermis - the deep vascular inner layer of the skin
  • Detoxification - treatment for poisoning by neutralizing the toxic properties (normally a function of the liver); a treatment for addiction to drugs or alcohol intended to remove the physiological effects of the addictive substances
  • Dextrocardia - abnormal condition where the heart is located toward the right side of the chest
  • Dextrose - an isomer of glucose that is found in honey and sweet fruits
  • Diabetes insipidus - a rare form of diabetes resulting from a deficiency of vasopressin (the pituitary hormone that regulates the kidneys); characterized by the chronic excretion of large amounts of pale dilute urine which results in dehydration and extreme thirst
  • Diabetes mellitus - diabetes caused by a relative or absolute deficiency of insulin and characterized by polyuria
  • Dialysis - separation of substances in solution by means of their unequal diffusion through semipermeable membranes
  • Diaper rash - dermatitis of the thighs and buttocks of infants; supposedly caused by ammonia in the urine in the child's diapers
  • Diaphragm - a mechanical device in a camera that controls size of aperture of the lens; electro acoustic transducer that vibrates to receive or produce sound waves; a contraceptive device consisting of a flexible dome shaped cup made of rubber or plastic; it is filled with spermicide and fitted over the uterine cervix; (anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
  • Diastolic pressure - the blood pressure (as measured by a sphygmomanometer) after the contraction of the heart while the chambers of the heart refill with blood
  • Diathermy - a method of physical therapy that involves generating local heat in body tissues by high frequency electromagnetic currents
  • Dilatation and Curettage - a surgical procedure usually performed under local anesthesia in which the cervix is dilated and the endometrial lining of the uterus is scraped with a curet; performed to obtain tissue samples or to stop prolonged bleeding or to remove small tumors or to remove fragments of placenta after childbirth or as a method of abortion
  • Diphtheria - acute contagious infection caused by the bacterium Corynebacterium diphtheriae; marked by the formation of a false membrane in the throat and other air passages causing difficulty in breathing
  • Dislocation - the act of disrupting an established order so it fails to continue; an event that results in a displacement or discontinuity; a displacement of a part (especially a bone) from its normal position (as in the shoulder or the vertebral column)
  • Distention - the act of expanding by pressure from within; the state of being stretched beyond normal dimensions
  • Diuretic - any substance that tends to increase the flow of urine
  • Diverticulitis - inflammation of a diverticulum in the digestive tract (especially the colon); characterized by painful abdominal cramping and fever and constipation
  • DNA - (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information
  • Dominant gene - gene that produces the same phenotype in the organism whether or not its allele identical
  • Dopamine - a monoamine neurotransmitter found in the brain and essential for the normal functioning of the central nervous system; as a drug (trade names Dopastat and Intropin) it is used to treat shock and hypotension
  • Down syndrome - a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation
  • Duodenum - the part of the small intestine between the stomach and the jejunum
  • Dysentery - an infection of the intestines marked by severe diarrhea
  • Dyspnea - difficult or labored respiration
  • Dystrophy - any degenerative disorder resulting from inadequate or faulty nutrition; any of several hereditary diseases of the muscular system characterized by weakness and wasting of skeletal muscles
  • Eardrum - the membrane in the ear that vibrates to sound
  • ECG - a graphical recording of the cardiac cycle produced by an electrocardiograph
  • Echocardiogram - a graphical image of the heart produced by an echocardiograph
  • Eclampsia - a toxic condition characterized by convulsions and possibly coma during or immediately after pregnancy
  • Eczema - generic term for inflammatory conditions of the skin; particularly with vesiculation in the acute stages
  • Edema - swelling from excessive accumulation of serous fluid in tissue
  • EEG - a graphical record of electrical activity of the brain; produced by an electroencephalograph
  • Elective - subject to popular election; not compulsory;  a course that the student can select from among alternatives
  • Embolism - occlusion of a blood vessel by an embolus (a loose clot or air bubble or other particle); an insertion into a calendar
  • Embryo - an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life; (botany) a minute rudimentary plant contained within a seed or an archegonium
  • Emetic - a medicine that induces nausea and vomiting
  • Emphysema - an abnormal condition of the lungs marked by decreased respiratory function; associated with smoking or chronic bronchitis or old age
  • Encephalitis - inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use)
  • Endarterectomy - surgical removal of the inner lining of an artery that is clogged with atherosclerosis
  • Endemic - native to or confined to a certain region; of or relating to a disease (or anything resembling a disease) constantly present to greater or lesser extent in a particular locality; originating where it is found;  a plant that is native to a certain limited area; a disease that is constantly present to a greater or lesser degree in people of a certain class or in people living in a particular location
  • Endocarditis - inflammation of the endocardium and heart valves
  • Endocardium - the membrane that lines the cavities of the heart and forms part of the heart valves
  • Endocrine gland - any of the glands of the endocrine system that secrete hormones directly into the bloodstream
  • Endogenous - derived or originating internally; of or resembling an endogen
  • Endometriosis - the presence of endometrium elsewhere than in the lining of the uterus; causes premenstrual pain and dysmenorrhea
  • Endometrium - (pregnancy) the mucous membrane that lines the uterus; thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation; if pregnancy occurs it is shed along with the placenta at parturition
  • Endorphin - a neurochemical occurring naturally in the brain and having analgesic properties
  • Endoscope - a long slender medical instrument for examining the interior of a bodily organ or performing minor surgery
  • Endothelium - an epithelium of mesoblastic origin; a thin layer of flattened cells that lines the inside of some body cavities
  • Endotracheal tube - a catheter that is inserted into the trachea through the mouth or nose in order to maintain an open air passage or to deliver oxygen or to permit the suctioning of mucus or to prevent aspiration of the stomach contents
  • Enteritis - inflammation of the intestine (especially the small intestine); usually characterized by diarrhea
  • Enterobiasis - an infestation with or a resulting infection caused by the pinworm Enterobius vermicularis; occurs especially in children
  • Enuresis - inability to control the flow of urine and involuntary urination
  • Enzyme - any of several complex proteins that are produced by cells and act as catalysts in specific biochemical reactions
  • Epidemic - (especially of medicine) of disease or anything resembling a disease; attacking or affecting many individuals in a community or a population simultaneously;  a widespread outbreak of an infectious disease; many people are infected at the same time
  • Epidermis - the outer layer of the skin covering the exterior body surface of vertebrates
  • Epididymis - a convoluted tubule in each testis; carries sperm to vas deferens
  • Epidural anesthesia - regional anesthesia resulting from injection of an anesthetic into the epidural space of the spinal cord; sensation is lost in the abdominal and genital and pelvic areas; used in childbirth and gynecological surgery
  • Epilepsy - a disorder of the central nervous system characterized by loss of consciousness and convulsions
  • Epinephrine - a catecholamine secreted by the adrenal medulla in response to stress (trade name Adrenalin); stimulates autonomic nerve action
  • Episiotomy - surgical incision of the perineum to enlarge the vagina and so facilitate delivery during childbirth
  • Epithelium - membranous tissue covering internal organs and other internal surfaces of the body
  • Erysipelas - an acute streptococcal infection characterized by deep red inflammation of the skin and mucous membranes
  • Erythema - abnormal redness of the skin resulting from dilation of blood vessels (as in sunburn or inflammation)
  • Erythrocyte - a mature blood cell that contains hemoglobin to carry oxygen to the bodily tissues; a biconcave disc that has no nucleus
  • Erythrocyte sedimentation rate - the rate at which red blood cells settle out in a tube of blood under standardized conditions; a high rate usually indicates the presence of inflammation
  • Esophagus - the passage between the pharynx and the stomach
  • Estrogen - a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics
  • Eustachian tube - either of the paired tubes connecting the middle ears to the nasopharynx; equalizes air pressure on the two sides of the eardrum
  • Euthanasia - the act of killing someone painlessly (especially someone suffering from an incurable illness)
  • Excision - the act of pulling up or out; uprooting; cutting off from existence; the act of banishing a member of a church from the communion of believers and the privileges of the church; cutting a person off from a religious society; surgical removal of a body part or tissue; the omission that is made when an editorial change shortens a written passage
  • Excretion - the bodily process of discharging waste matter; waste matter (as urine or sweat but especially feces) discharged from the body
  • Exogenous - derived or originating externally
  • Extensor muscle - a skeletal muscle whose contraction extends or stretches a body part
  • Fallopian tube - either of a pair of tubes conducting the egg from the ovary to the uterus
  • Familial - tending to occur among members of a family usually by heredity; relating to or having the characteristics of a family
  • Fatty acid - any of a class of aliphatic monocarboxylic acids that form part of a lipid molecule and can be derived from fat by hydrolysis; fatty acids are simple molecules built around a series of carbon atoms linked together in a chain of 12 to 22 carbon atoms
  • Febrile - of or relating to or characterized by fever
  • Femoral artery - the chief artery of the thigh; a continuation of the external iliac artery
  • Femur - the longest and thickest bone of the human skeleton; extends from the pelvis to the knee
  • Fertility - the state of being fertile; capable of producing offspring; the property of producing abundantly and sustaining vigorous and luxuriant growth; the ratio of live births in an area to the population of that area; expressed per 1000 population per year
  • Fertilization - making fertile as by applying fertilizer or manure; creation by the physical union of male and female gametes; of sperm and ova in an animal or pollen and ovule in a plant
  • Fetal alcohol syndrome - a medical condition in which body deformation or facial development or mental ability of a fetus is impaired because the mother drank alcohol while pregnant
  • Fetal distress - an abnormal condition of a fetus; usually discovered during pregnancy and characterized by an abnormal heart rhythm
  • Fetus - an unborn or unhatched vertebrate in the later stages of development showing the main recognizable features of the mature animal
  • Fiber - a leatherlike material made by compressing layers of paper or cloth; a slender and greatly elongated solid substance; the inherent complex of attributes that determine a persons moral and ethical actions and reactions
  • Fiberoptics - the transmission of light signals via glass fibers
  • Fibrillation - act or process of forming fibrils; muscular twitching involving individual muscle fibers acting without coordination
  • Fibroadenoma - benign and movable and firm and not tender tumor of the breast; common in young women and caused by high levels of estrogen
  • Fibroid - benign tumor containing fibrous tissue (especially in the uterus)
  • Fibroma - nonmalignant tumor of connective tissue
  • Fibrosis - development of excess fibrous connective tissue in an organ
  • Fissure - (anatomy) a long narrow slit or groove that divides an organ into lobes; a long narrow opening; a long narrow depression in a surface; verb break into fissures or fine cracks
  • Fistula - an abnormal passage leading from a suppurating cavity to the body surface; a chronic inflammation of the withers of a horse
  • Fitness - the condition of being suitable; the quality of being qualified; good physical condition; being in shape or in condition; fitness to traverse the seas
  • Flatulence - a state of excessive gas in the alimentary canal; pompously embellished language
  • Flu - an acute febrile highly contagious viral disease
  • Fluke - parasitic flatworms having external suckers for attaching to a host; either of the two lobes of the tail of a cetacean; flat bladelike projection on the arm of an anchor; a barb on a harpoon or arrow; a stroke of luck
  • Fluoroscopy - examination of body structures using a fluoroscope
  • Folic acid - a B vitamin that is essential for cell growth and reproduction
  • Follicle - any small spherical group of cells containing a cavity
  • Forceps - an extractor consisting of a pair of pincers used in medical treatment (especially for the delivery of babies)
  • Forceps delivery - delivery in which forceps are inserted through the vagina and used to grasp the head of the fetus and pull it through the birth canal; since the forceps can injure the fetus this procedure has generally given way to cesarean deliveries
  • Foreskin - a fold of skin covering the tip of the penis; a fold of skin covering the tip of the clitoris
  • Fracture - the act of cracking something; breaking of hard tissue such as bone; (geology) a crack in the earth's crust resulting from the displacement of one side with respect to the other; verb fracture a bone of; break (a bone); become fractured; violate or abuse; break into pieces; interrupt, break, or destroy
  • Free radical - an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule than has lost an electron and will stabilize itself by stealing an electron from a nearby molecule
  • Frostbite - destruction of tissue by freezing and characterized by tingling, blistering and possibly gangrene
  • FSH - a gonadotropic hormone that is secreted by the anterior pituitary and stimulates growth of Graafian follicles in female mammals, and activates the cells in male mammals that form sperm
  • Fungus - a parasitic plant lacking chlorophyll and leaves and true stems and roots and reproducing by spores
  • Galactosemia - a genetic disease (autosomal recessive) in which an enzyme needed to metabolize galactose is deficient or absent; typically develops shortly after birth
  • Gallbladder - a muscular sac attached to the liver that secretes bile and stores it until needed for digestion
  • Gallstone - a calculus formed in the gall bladder or its ducts
  • Gamma globulin - a plasma protein containing the immunoglobulins that are responsible for immune responses
  • Ganglion - an encapsulated neural structure consisting of a collection of cell bodies or neurons
  • Gangrene - necrotic tissue; a mortified or gangrenous part or mass; the localized death of living cells (as from infection or the interruption of blood supply); verb undergo necrosis
  • Gastrectomy - surgical removal of all or part of the stomach
  • Gastric juice - digestive secretions of the stomach glands consisting chiefly of hydrochloric acid and mucin and the enzymes pepsin and rennin and lipase
  • Gastric lavage - washing out the stomach with sterile water or a saltwater solution; removes blood or poisons
  • Gastrin - polypeptide hormone secreted by the mucous lining of the stomach; induces the secretion of gastric juice
  • Gastritis - inflammation of the lining of the stomach; nausea and loss of appetite and discomfort after eating
  • Gastroenteritis - inflammation of the stomach and intestines; can be caused by Salmonella enteritidis
  • Gastrointestinal tract - tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination
  • Gastroscopy - visual examination of the stomach by means of a gastroscope inserted through the esophagus
  • Gastrostomy - surgical creation of an opening through the abdominal wall into the stomach (as for gastrogavage)
  • Gavage - feeding that consists of the delivery of a nutrient solution (as through a nasal tube) to someone who cannot or will not eat
  • Gene - (genetics) a segment of DNA that is involved in producing a polypeptide chain; it can include regions preceding and following the coding DNA as well as introns between the exons; it is considered a unit of heredity
  • General anesthesia - a state of total unconsciousness resulting from anesthetic drugs (as for a major surgical operation)
  • Generic drug - when the patent protection for a brand name drug expires generic versions of the drug can be offered for sale if the FDA agrees
  • Genetic counseling - guidance for prospective parents on the likelihood of genetic disorders in their future children
  • Genetic engineering - the technology of preparing recombinant DNA in vitro by cutting up DNA molecules and splicing together fragments from more than one organism
  • Genital herpes - an infection caused by herpes simplex virus type 2 (HSV 2) that is usually transmitted by sexual contact; marked by recurrent attacks of painful eruptions on the skin and mucous membranes of the genital area
  • Genital wart - a small benign wart on or around the genitals and anus
  • Genome - the ordering of genes in a haploid set of chromosomes of a particular organism; the full DNA sequence of an organism
  • German measles - a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester
  • Gestation - the conception and development of an idea or plan; the period during which an embryo develops (about 266 days in humans); the state of being pregnant; the period from conception to birth when a woman carries a developing fetus in her uterus
  • Giardiasis - infection of the intestines with protozoa found in contaminated food and water; characterized by diarrhea and nausea and flatulence and abdominal discomfort
  • GIFT - something acquired without compensation; the act of giving; natural abilities or qualities; verb give as a present; make a gift of; give qualities or abilities to
  • GI series - diagnostic tests of the alimentary canal; usually involves inserting a contrast medium (such as barium sulfate) and taking an X ray
  • Gland - any of various organs that synthesize substances needed by the body and release it through ducts or directly into the bloodstream
  • Glaucoma - increased pressure in the eyeball due to obstruction of the outflow of aqueous humor; damages the optic disc and impairs vision (sometimes progressing to blindness)
  • Glioma - a tumor of the brain consisting of neuroglia
  • Glomerulonephritis - nephritis marked by inflammation of the glomeruli of the kidney; characterized by decreased production of urine and by the presence of blood and protein in the urine and by edema
  • Glucagon - a hormone secreted by the pancreas; stimulates increases in blood sugar levels in the blood (thus opposing the action of insulin)
  • Glucose - a monosaccharide sugar that has several forms; an important source of physiological energy
  • Glucose tolerance test - test of the body's ability to metabolize carbohydrates; used in the diagnosis of hypoglycemia and diabetes mellitus
  • Glycogen - one form in which body fuel is stored; stored primarily in the liver and broken down into glucose when needed by the body
  • Glycosuria - the presence of abnormally high levels of sugar in the urine
  • Goiter - abnormally enlarged thyroid gland; can result from underproduction or overproduction of hormone or from a deficiency of iodine in the diet
  • Gonorrhea - a common venereal disease caused by the bacterium Neisseria gonorrhoeae; symptoms are painful urination and pain around the urethra
  • Gout - a painful inflammation of the big toe and foot caused by defects in uric acid metabolism resulting in deposits of the acid and its salts in the blood and joints
  • Graft - the act of grafting something onto something else; (surgery) tissue or organ transplanted from a donor to a recipient; in some cases the patient can be both donor and recipient; the practice of offering something (usually money) in order to gain an illicit advantage; verb cause to grow together parts from different plants; place the organ of a donor into the body of a recipient
  • Grand mal - a seizure (or a type of epilepsy characterized by such seizures) during which the patient becomes unconscious and has convulsions over the entire body
  • Granuloma - a tumor composed of granulation tissue resulting from injury or inflammation or infection
  • Graves' disease - exophthalmos occurring in association with goiter; hyperthyroidism with protrusion of the eyeballs
  • syndrome - a complex of concurrent things; a pattern of symptoms indicative of some disease
  • Hallucination - an object perceived during a hallucinatory episode; illusory perception; a common symptom of severe mental disorder; a mistaken or unfounded opinion or idea
  • Hay fever - a seasonal rhinitis resulting from an allergic reaction to pollen
  • HDL - a lipoprotein that transports cholesterol in the blood; composed of a high proportion of protein and relatively little cholesterol; high levels are thought to be associated with decreased risk of coronary heart disease and atherosclerosis
  • Heart attack - a sudden severe instance of abnormal heart function
  • Heart block - recurrent sudden attacks of unconsciousness caused by impaired conduction of the impulse that regulates the heartbeat
  • Heartburn - a painful burning sensation in the chest caused by gastroesophageal reflux (backflow from the stomach irritating the esophagus); symptomatic of an ulcer or a diaphragmatic hernia or other disorder
  • Heart failure - inability of the heart to pump enough blood to sustain normal bodily functions
  • Heart rate - the rate at which the heart beats; usually measured to obtain a quick evaluation of a person's health
  • Heart valve - an implant that replaces a natural cardiac valve; a valve to control one way flow of blood
  • Heat exhaustion - a condition marked by dizziness and nausea and weakness caused by depletion of body fluids and electrolytes
  • Heimlich maneuver - an emergency procedure to help someone who is choking because food is lodged in the trachea
  • Hemangioma - benign angioma consisting of a mass of blood vessels; some appear as birthmarks
  • Hematocrit - a measuring instrument to determine (usually by centrifugation) the relative amounts of corpuscles and plasma in the blood; the ratio of the volume occupied by packed red blood cells to the volume of the whole blood as measured by a hematocrit
  • Hematoma - a localized swelling filled with blood
  • Hematuria - the presence of blood in the urine; often a symptom of urinary tract disease
  • Hemochromatosis - pathology in which iron accumulates in the tissues; characterized by bronzed skin and enlarged liver and diabetes mellitus and abnormalities of the pancreas and the joints
  • Hemodialysis - dialysis of the blood to remove toxic substances or metabolic wastes from the bloodstream; used in the case of kidney failure
  • Hemoglobin - a hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues
  • Hemolysis - lysis of erythrocytes with the release of hemoglobin
  • Hemophilia - congenital tendency to uncontrolled bleeding; usually affects males and is transmitted from mother to son
  • Hemorrhage - flow of blood from a ruptured blood vessels; verb lose blood from one's body
  • Hemorrhoid - pain caused by venous swelling at or inside the anal sphincter
  • Hemostasis - surgical procedure of stopping the flow of blood (as with a hemostat)
  • Hemothorax - accumulation of blood in the pleural cavity (the space between the lungs and the walls of the chest)
  • Hepatic - pertaining to or affecting the liver;  any of numerous small green nonvascular plants of the class Hepaticopsida growing in wet places and resembling green seaweeds or leafy mosses
  • Hepatitis - inflammation of the liver caused by a virus or a toxin
  • Hepatitis A - an acute but benign form of viral hepatitis caused by an RNA virus that does not persist in the blood serum and is usually transmitted by ingesting food or drink that is contaminated with fecal matter
  • Hepatitis B - an acute (sometimes fatal) form of viral hepatitis caused by a DNA virus that tends to persist in the blood serum and is transmitted by sexual contact or by transfusion or by ingestion of contaminated blood or other bodily fluids
  • Hepatitis C - a viral hepatitis clinically indistinguishable from hepatitis B but caused by a single stranded RNA virus; usually transmitted by parenteral means (as injection of an illicit drug or blood transfusion or exposure to blood or blood products)
  • Hereditary - inherited or inheritable by established rules (usually legal rules) of descent; tending to occur among members of a family usually by heredity
  • Hermaphroditism - congenital condition in which external genitalia and internal sex organs have both male and female characteristics; showing characteristics of both sexes
  • Hernia - rupture in smooth muscle tissue through which a bodily structure protrudes
  • Herpes encephalitis - common form of acute encephalitis caused by herpes simplex 1; usually affects the temporal and frontal lobes
  • Herpes simplex - a herpes virus that affects the skin and nervous system; an infection caused by the herpes simples virus; affects the skin and nervous system; produces small temporary (but sometimes painful) blisters on the skin and mucous membranes
  • Herpes zoster - a herpes virus that causes shingles; eruptions along a nerve path often accompanied by severe neuralgia
  • Heterosexuality - a sexual attraction to (or sexual relations with) persons of the opposite sex
  • Hiatal hernia - hernia resulting from the protrusion of part of the stomach through the diaphragm
  • Hiccup - (usually plural) the state of having reflex spasms of the diaphragm accompanied by a rapid closure of the glottis producing an audible sound; sometimes a symptom of indigestion; verb breathe spasmodically, and make a sound
  • Hirschsprung's disease - congenital condition in which the colon does not have the normal network of nerves; there is little urge to defecate so the feces accumulate and cause megacolon
  • Histamine - amine formed from histidine that stimulates gastric secretions and dilates blood vessels; released by the human immune system during allergic reactions
  • histamine - amine formed from histidine that stimulates gastric secretions and dilates blood vessels; released by the human immune system during allergic reactions
  • blocker - a class of drugs that inhibit (block) some biological process; a football player whose responsibility is to block players attempting to stop an offensive play
  • histamine - amine formed from histidine that stimulates gastric secretions and dilates blood vessels; released by the human immune system during allergic reactions
  • blocker - a class of drugs that inhibit (block) some biological process; a football player whose responsibility is to block players attempting to stop an offensive play
  • HIV - infection by the human immunodeficiency virus; the virus that causes acquired immune deficiency syndrome (AIDS); it replicates in and kills the helper T cells
  • Hives - an itchy skin eruption characterized by weals with pale interiors and well defined red margins; usually the result of an allergic response to insect bites or food or drugs
  • Hodgkin's disease - a malignant disorder in which there is progressive (but painless) enlargement of lymph tissue followed by enlargement of the spleen and liver
  • Homeostasis - (physiology) metabolic equilibrium actively maintained by several complex biological mechanisms that operate via the autonomic nervous system to offset disrupting changes
  • Homosexuality - a sexual attraction to (or sexual relations with) persons of the same sex
  • Hookworm - parasitic bloodsucking roundworms having hooked mouth parts to fasten to the intestinal wall of human and other hosts; infestation of the intestines by hookworms which enter the body (usually) through the skin
  • Hormone - the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect
  • Hormone replacement therapy - hormones (estrogen and progestin) are given to postmenopausal women; believed to protect them from heart disease and osteoporosis
  • Hospice - a program of medical and emotional care for the terminally ill; a lodging for travelers (especially one kept by a monastic order)
  • Hot flash - sudden brief sensation of heat (associated with menopause and some mental disorders)
  • Human immunodeficiency virus - the virus that causes acquired immune deficiency syndrome (AIDS); it replicates in and kills the helper T cells
  • Hydramnios - an abnormality of pregnancy; accumulation of excess amniotic fluid
  • Hydrocele - disorder in which serous fluid accumulates in a body sac (especially in the scrotum)
  • Hydrocephalus - an abnormal condition in which cerebrospinal fluid collects in the ventricles of the brain; in infants it can cause abnormally rapid growth of the head and bulging fontanelles and a small face; in adults the symptoms are primarily neurological
  • Hydrocortisone - an adrenal cortex hormone (trade names Hydrocortone or Cortef) that is active in carbohydrate and protein metabolism
  • Hygiene - the science concerned with the prevention of illness and maintenance of health; a condition promoting sanitary practices
  • Hymen - a fold of tissue that partly covers the entrance to the vagina of a virgin; (Greek mythology) the god of marriage
  • Hyperactivity - a condition characterized by excessive restlessness and movement
  • Hyperalimentation - administration of a nutritionally adequate solution through a catheter into the vena cava; used in cases of long term coma or severe burns or severe gastrointestinal syndromes
  • Hypercalcemia - the presence of abnormally high levels of calcium in the blood; usually the result of excessive bone resorption in hyperparathyroidism or Paget's disease
  • Hypercholesterolemia - the presence of an abnormal amount of cholesterol in the cells and plasma of the blood; associated with the risk of atherosclerosis
  • Hyperglycemia - abnormally high blood sugar usually associated with diabetes
  • Hyperparathyroidism - excessive secretion of parathyroid hormone resulting in abnormally high levels of calcium in the blood; can affect many systems of the body (especially causing bone resorption and osteoporosis)
  • Hypertension - a common disorder in which blood pressure remains abnormally high (a reading of 140/90 mm Hg or greater)
  • Hyperthermia - abnormally high body temperature; sometimes induced (as in treating some forms of cancer)
  • Hyperthyroidism - an overactive thyroid gland; pathologically excessive production of thyroid hormones or the condition resulting from excessive production of thyroid hormones
  • Hypertrophy - abnormal enlargement of a body part or organ; verb undergo hypertrophy
  • Hyperventilation - an increased depth and rate of breathing greater than demanded by the body needs; can cause dizziness and tingling of the fingers and toes and chest pain if continued
  • Hypochondriasis - chronic and abnormal anxiety about imaginary symptoms and ailments
  • Hypoglycemia - abnormally low blood sugar usually resulting from excessive insulin or a poor diet
  • Hypoplasia - underdevelopment of an organ because of a decrease in the number of cells
  • Hypothyroidism - an underactive thyroid gland; a glandular disorder resulting from insufficient production of thyroid hormones
  • Hypoxia - a very strong drive resulting from a deficiency of available oxygen in the blood and bodily tissues (short of anoxia)
  • Hysteria - excessive or uncontrollable fear; neurotic disorder characterized by violent emotional outbreaks and disturbances of sensory and motor functions; state of violent mental agitation
  • Hysteroscopy - visual examination of the uterus and uterine lining using an endoscope inserted through the vagina
  • Ichthyosis - any of several congenital diseases in which the skin is fishlike (dry and scaly)
  • Idiopathic - (of diseases) arising from an unknown cause
  • Ileostomy - surgical procedure that creates an opening from the ileum through the abdominal wall to function as an anus; performed in cases of cancer of the colon or ulcerative colitis
  • Ileum - the part of the small intestine between the jejunum and the cecum
  • Ilium - the upper and widest of the three bones making up the hipbone; an ancient city in Asia Minor that was the site of the Trojan War
  • Imaging - (medicine) obtaining pictures of the interior of the body; the ability to form mental images of things or events
  • Immune system - a system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response
  • Immunity - the quality of being unaffected by something; (medicine) the condition in which an organism can resist disease; an act exempting someone; the state of not being susceptible
  • Immunization - the act of making immune (especially by inoculation)
  • Immunocompromised - unable to develop a normal immune response usually because of malnutrition or immunodeficiency or immunosuppressive therapy
  • Immunodeficiency - immunological disorder in which some part of the body's immune system is inadequate and resistance to infectious diseases is reduced
  • Immunology - the branch of medical science that studies the body's immune system
  • Impacted fracture - fracture in which one broken end is wedged into the other broken end
  • Imperforate anus - a congenital defect of the anus; there is partial or complete obstruction of the anal opening
  • Impetigo - a very contagious infection of the skin; common in children; localized redness develops into small blisters that gradually crust and erode
  • Implant - a prosthesis placed permanently in tissue; verb become attached to and embedded in the uterus; fix or set securely or deeply; put firmly in the mind
  • Impotence - an inability (usually of the male animal) to copulate; the quality of lacking strength or power; being weak and feeble
  • Incompetent cervix - (obstetrics) uterine cervix that becomes dilated before term and without labor often resulting in miscarriage or premature birth
  • Incontinence - involuntary urination or defecation; indiscipline with regard to sensuous pleasures
  • Incubation period - the period between infection and the appearance of symptoms of the disease
  • Indigestion - a disorder of digestive function characterized by discomfort or heartburn or nausea
  • Induction of labor - (obstetrics) inducing the childbirth process artificially by administering oxytocin or by puncturing the amniotic sac
  • Infarction - localized necrosis resulting from obstruction of the blood supply
  • Infection - (international law) illegality that taints or contaminates a ship or cargo rendering it liable to seizure; moral corruption or contamination; an incident in which an infectious disease is transmitted; (medicine) the invasion of the body by pathogenic microorganisms and their multiplication which can lead to tissue damage and disease; (phonetics) the alteration of a speech sound under the influence of a neighboring sound; the pathological state resulting from the invasion of the body by pathogenic microorganisms; the communication of an attitude or emotional state among a number of people
  • Infertility - the state of being unable to produce offspring; in a woman it is an inability to conceive; in a man it is an inability to impregnate
  • Inflammation - arousal to violent emotion; a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat; the act of setting something on fire; the state of being emotionally aroused and worked up
  • Influenza - an acute febrile highly contagious viral disease
  • Informed consent - consent by a patient to undergo a medical or surgical treatment or to participate in an experiment after the patient understands the risks involved
  • Infusion - the act of infusing or introducing a certain modifying element or quality; (medicine) the passive introduction of a substance (a fluid or drug or electrolyte) into a vein or between tissues (as by gravitational force); the process of extracting certain active properties (as a drug from a plant) by steeping or soaking (usually in water); a solution obtained by steeping or soaking a substance (usually in water)
  • Ingestion - the process of taking food into the body through the mouth (as by eating)
  • Ingrown toenail - toenail having its free tip or edges embedded in the surrounding flesh
  • Inguinal hernia - hernia in which a loop of intestine enters the inguinal canal; the most common type of hernia in males
  • Inhaler - a dispenser that produces a chemical vapor to be inhaled in order to relieve nasal congestion
  • Inheritance - hereditary succession to a title or an office or property; any attribute or immaterial possession that is inherited from ancestors; (genetics) attributes acquired via biological heredity from the parents; that which is inherited; a title or property or estate that passes by law to the heir on the death of the owner
  • Injection - the forceful insertion of a substance under pressure; the act of putting a liquid into the body by means of a syringe; any solution that is injected (as into the skin)
  • Insemination - the introduction of semen into the genital tract of a female; the act of sowing (of seeds in the ground or, figuratively, of germs in the body or ideas in the mind, etc.)
  • In situ - being in the original position; not having been moved
  • Insomnia - an inability to sleep; chronic sleeplessness
  • Insulin - hormone secreted by the isles of Langerhans in the pancreas; regulates storage of glycogen in the liver and accelerates oxidation of sugar in cells
  • Intensive care - close monitoring and constant medical care of patients with life threatening conditions
  • Interferon - an antiviral protein produced by cells that have been invaded by a virus; inhibits replication of the virus
  • Intestinal bypass - surgical operation that shortens the small intestine; used in treating obesity
  • Intestine - the part of the alimentary canal between the stomach and the anus
  • Intractable - not tractable; difficult to manage or mold
  • Intraocular pressure - pressure inside the eyeball; regulated by resistance to the outward flow of aqueous humor
  • Intrauterine device - contraceptive device consisting of a piece of bent plastic or metal that is inserted through the vagina into the uterus
  • Intrinsic - situated within or belonging solely to the organ or body part on which it acts; belonging to a thing by its very nature
  • Intubation - the insertion of a cannula or tube into a hollow body organ
  • Invasive - marked by a tendency to spread especially into healthy tissue; relating to a technique in which the body is entered by puncture or incision; gradually intrusive without right or permission; involving invasion or aggressive attack
  • In vitro - in an artificial environment outside the living organism;  in an artificial environment outside the living organism
  • In vivo - within a living organism;  in the living organism
  • Involuntary - not subject to the control of the will; controlled by the autonomic nervous system; without conscious control
  • Iodine - a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks); a tincture consisting of a solution of iodine in ethyl alcohol; applied topically to wounds as an antiseptic
  • Ionizing radiation - high energy radiation capable of producing ionization in substances through which it passes
  • IQ - a measure of a person's intelligence as indicated by an intelligence test; the ratio of a person's mental age to their chronological age (multiplied by 100)
  • Iris - diaphragm consisting of thin overlapping plates that can be adjusted to change the diameter of a central opening; muscular diaphragm that controls the size of the pupil; it forms the colored portion of the eye; plants with sword shaped leaves and erect stalks bearing bright colored flowers composed of three petals and three drooping sepals
  • Iron - extremely robust;  home appliance consisting of a flat metal base that is heated and used to smooth cloth; a golf club that has a relatively narrow metal head; implement used to brand live stock; a heavy ductile magnetic metallic element; is silver white in pure form but readily rusts; used in construction and tools and armament; plays a role in the transport of oxygen by the blood; verb press and smooth with a heated iron
  • Iron deficiency anemia - a form of anemia due to lack of iron in the diet or to iron loss as a result of chronic bleeding
  • Irrigation - (medicine) cleaning a wound or body organ by flushing or washing out with water or a medicated solution; supplying dry land with water by means of ditches etc
  • Irritable bowel syndrome - recurrent abdominal pain and diarrhea (often alternating with periods of constipation); often associated with emotional stress
  • Ischemia - local anemia in a given body part sometimes resulting from vasoconstriction or thrombosis or embolism
  • IUD - contraceptive device consisting of a piece of bent plastic or metal that is inserted through the vagina into the uterus
  • Jock itch - fungal infection of the groin (most common in men)
  • Juvenile rheumatoid arthritis - a form of rheumatoid arthritis that affects children; large joints become inflamed and bone growth may be retarded
  • Kawasaki disease - an acute disease of young children characterized by a rash and swollen lymph nodes and fever; of unknown cause
  • Keloid - raised pinkish scar tissue at the site of an injury; results from excessive tissue repair
  • Keratin - a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair feathers nails and hooves
  • Keratitis - inflammation of the cornea causing watery painful eyes and blurred vision
  • Keratoplasty - a surgical procedure in which part or all of a damaged or diseased cornea is replaced by healthy corneal tissue from a donor
  • Keratosis - a skin condition marked by an overgrowth of layers of horny skin
  • Ketoacidosis - acidosis with an accumulation of ketone bodies; occurs primarily in diabetes mellitus
  • Kidney - either of two bean shaped excretory organs that filter wastes (especially urea) from the blood and excrete them and water in urine
  • Kilocalorie - a unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure; used by nutritionists to characterize the energy producing potential in food
  • Klinefelter - United States physician who first described the XXY syndrome (born in 1912)
  • Kyphosis - an abnormal backward curve to the vertebral column
  • Labor - productive work (especially physical work done for wages); a social class comprising those who do manual labor or work for wages; any piece of work that is undertaken or attempted; the federal department responsible for promoting the working conditions of wage earners in the United States; created in 1913; a political party formed in Great Britain in 1900; characterized by the promotion of labor's interests and the socialization of key industries; an organized attempt by workers to improve their status by united action (particularly via labor unions) or the leaders of this movement; concluding state of pregnancy; from the onset of labor to the birth of a child; verb undergo the efforts of childbirth; work hard; strive and make an effort to reach a goal
  • Labyrinthitis - inflammation of the inner ear; can cause vertigo and vomiting
  • Laceration - the act of lacerating; a torn ragged wound
  • Lactase deficiency - congenital disorder consisting of an inability to digest milk and milk products; absence or deficiency of lactase results in an inability to hydrolyze lactose
  • Lactation - the production and secretion of milk by the mammary glands; the period following birth during which milk is secreted; feeding an infant by giving suck at the breast
  • Lactic acid - a clear odorless hygroscopic syrupy carboxylic acid found in sour milk and in many fruits
  • Lactose - a sugar comprising one glucose molecule linked to a galactose molecule; occurs only in milk
  • Lactose intolerance - congenital disorder consisting of an inability to digest milk and milk products; absence or deficiency of lactase results in an inability to hydrolyze lactose
  • Lamaze method - a method that prepares a mother for natural childbirth; the pregnant woman (in classes and at home) practices (usually with the help of a coach) learns about the physiology of childbirth and techniques of relaxation and concentration and breathing
  • Laminectomy - surgical removal of the bony arches on one or more vertebrae
  • Laparoscope - a slender endoscope inserted through an incision in the abdominal wall in order to examine the abdominal organs or to perform minor surgery
  • Laparoscopic cholecystectomy - removal of the gall bladder through small punctures in the abdomen to permit the insertion of a laparoscope and surgical instruments
  • Laparoscopy - laparotomy performed with a laparoscope that makes a small incision to examine the abdominal cavity (especially the ovaries and Fallopian tubes)
  • Large intestine - beginning with the cecum and ending with the rectum; includes the cecum and the colon and the rectum; extracts moisture from food residues which are later excreted as feces
  • Laryngectomy - surgical removal of part or all of the larynx (usually to treat cancer of the larynx)
  • Laryngitis - inflammation of the mucous membrane of the larynx; characterized by hoarseness or loss of voice and coughing
  • Larynx - a cartilaginous structure at the top of the trachea; contains elastic vocal cords that are the source of the vocal tone in speech
  • Lateral - lying away from the median and sagittal plane of a body; situated at or extending to the side;  a pass to a receiver upfield from the passer
  • LDL - a lipoprotein that transports cholesterol in the blood; composed of moderate amount of protein and a large amount of cholesterol; high levels are thought to be associated with increased risk of coronary heart disease and atherosclerosis
  • Lead poisoning - toxic condition produced by the absorption of excessive lead into the system
  • Learning disability - a disorder found in children of normal intelligence who have difficulties in learning specific skills
  • disease - an impairment of health or a condition of abnormal functioning
  • Leiomyoma - benign tumor of smooth muscle (usually in the uterus or digestive tract)
  • Leishmaniasis - sores resulting from a tropical infection by protozoa of the genus Leishmania which are spread by sandflies
  • Leptospirosis - an infectious disease cause by leptospira and transmitted to humans from domestic animals; characterized by jaundice and fever
  • Lesion - any visible abnormal structural change in a bodily part; any break in the skin or an organ caused by violence or surgical incision
  • Leukemia - malignant neoplasm of blood forming tissues; characterized by abnormal proliferation of leukocytes; one of the four major types of cancer
  • Leukocyte - blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system
  • LH - a gonadotropic hormone that is secreted by the anterior pituitary; stimulates ovulation in female mammals and stimulates androgen release in male mammals
  • Lichen planus - an eruption of shiny flat topped purplish (usually itchy) papules on the wrist and forearms and thighs
  • Ligament - any connection or unifying bond; a sheet or band of tough fibrous tissue connecting bones or cartilages or supporting muscles or organs
  • Ligation - (surgery) tying a duct or blood vessel with a ligature (as to prevent bleeding during surgery)
  • Lipidosis - a disorder of lipid metabolism; abnormal levels of certain fats accumulate in the body
  • Lipoma - a tumor consisting of fatty tissue
  • Listeriosis - an infectious disease of animals and humans (especially newborn or immunosuppressed persons) caused by the bacterium Listeria monocytogenes; in sheep and cattle the infection frequently involves the central nervous system and causes various neurological symptoms
  • Liver - having a reddish brown color;  large and complicated reddish brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; synthesizes substances involved in the clotting of the blood; synthesizes vitamin A; detoxifies poisonous substances and breaks down worn out erythrocytes; liver of an animal used as meat; someone who lives in a place; a person who has a special life style
  • Lobe - a rounded projection that is part of a larger structure; (anatomy) a somewhat rounded subdivision of a bodily organ or part; the enhanced response of an antenna in a given direction as indicated by a loop in its radiation pattern; (botany) a part into which a leaf is divided
  • Lobectomy - surgical removal of a lobe from any organ of the body (as the lung or brain)
  • Local anesthesia - loss of sensation in a small area of the body (as when a local anesthetic is injected for a tooth extraction)
  • Lockjaw - an acute and serious infection of the central nervous system caused by bacterial infection of open wounds; spasms of the jaw and laryngeal muscles may occur during the late stages
  • Lordosis - an abnormal inward (forward) curvature of the vertebral column
  • Lou Gehrig's disease - thickening of tissue in the motor tracts of the lateral columns and anterior horns of the spinal cord; results in progressive muscle atrophy that starts in the limbs
  • Lumbago - backache affecting the lumbar region or lower back; can be caused by muscle strain or arthritis or vascular insufficiency or a ruptured intervertebral disc
  • Lumbar puncture - removal by centesis of fluid from the subarachnoid space of the lumbar region of the spinal cord for diagnostic or therapeutic purposes
  • Lumpectomy - surgical removal of a tumor without removing much of the surrounding tissue or lymph nodes; performed in some cases of breast cancer
  • Lupus erythematosus - a chronic inflammatory collagen disease affecting connective tissue (skin or joints)
  • Luteinizing hormone - a gonadotropic hormone that is secreted by the anterior pituitary; stimulates ovulation in female mammals and stimulates androgen release in male mammals
  • Lyme disease - an acute inflammatory disease characterized by a rash with joint swelling and fever; caused by bacteria carried by the bite of a deer tick
  • Lymph - a thin coagulable fluid (similar to plasma but) containing white blood cells (lymphocytes) and chyle; is conveyed to the blood stream by lymphatic vessels
  • Lymphadenopathy - chronic abnormal enlargement of the lymph nodes (usually associated with disease)
  • Lymphangiography - roentgenographic examination of lymph nodes and lymph vessels after injection of a radiopaque contrast medium; produces a lymphangiogram
  • Lymphatic system - the interconnected system of spaces and vessels between body tissues and organs by which lymph circulates throughout the body
  • Lymphocyte - an agranulocytic leukocyte that normally makes up a quarter of the white blood cell count but increases in the presence of infection
  • Lymphocytic leukemia - leukemia characterized by enlargement of lymphoid tissues and lymphocytic cells in the circulating blood
  • Lymphogranuloma venereum - infectious disease caused by a species of chlamydia bacterium; transmitted by sexual contact; characterized by genital lesions and swelling of lymph nodes in the groin
  • Macular degeneration - degeneration of the cells of the macula lutea which results in blurred vision and can cause blindness; usually age related
  • Magnesium - a light silver white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spinel and olivine)
  • MRI - the use of nuclear magnetic resonance of protons to produce proton density images
  • Malabsorption - abnormal absorption of nutrients from the digestive tract
  • Malaria - an infective disease caused by sporozoan parasites that are transmitted through the bite of an infected Anopheles mosquito; marked by paroxysms of chills and fever
  • Malformation - something abnormal or anomalous; an affliction in which some part of the body is misshapen or malformed
  • Malignant - dangerous to health; characterized by progressive and uncontrolled growth (especially of a tumor)
  • Malignant hyperthermia - hereditary condition in which certain anesthetics (e.g., halothane) cause high body temperatures and muscle rigidity
  • Malignant melanoma - any of several malignant neoplasms (usually of the skin) consisting of melanocytes
  • Mammography - a diagnostic procedure to detect breast tumors by the use of X rays
  • Mandible - the jaw in vertebrates that is hinged to open the mouth
  • Mania - an irrational but irresistible motive for a belief or action; a mood disorder; an affective disorder in which the victim tends to respond excessively and sometimes violently
  • Marfan's syndrome - an autosomal dominant disease characterized by elongated bones (especially of limbs and digits) and abnormalities of the eyes and circulatory system
  • Mast cell - a large connective tissue cell that contains histamine and heparin and serotonin which are released in allergic reactions or in response to injury or inflammation
  • Mastectomy - surgical removal of a breast to remove a malignant tumor
  • Mastitis - inflammation of a breast (or udder)
  • Maxilla - the jaw in vertebrates that is fused to the cranium
  • Measles - an acute and highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children
  • Meconium - thick dark green mucoid material that is the first feces of a newborn child
  • Medial - dividing an animal into right and left halves; relating to or situated in or extending toward the middle
  • Medulla - the inner part of an organ or structure in plant or animal; lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata); a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers
  • Megacolon - an abnormal enlargement of the colon; can be congenital (as in Hirschsprung's disease) or acquired (as when children refuse to defecate)
  • Megaloblastic anemia - anemia characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow; associated with pernicious anemia
  • Meiosis - (genetics) cell division that produces reproductive cells in sexually reproducing organisms; the nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants); understatement for rhetorical effect (especially when expressing an affirmative by negating its contrary)
  • Melanin - insoluble pigments that account for the color of e.g. skin and scales and feathers
  • Melanoma - any of several malignant neoplasms (usually of the skin) consisting of melanocytes
  • Menarche - the first occurrence of menstruation in a woman
  • Meniere's disease - a disease of the inner ear characterized by episodes of dizziness and tinnitus and progressive hearing loss (usually unilateral)
  • Meninges - a membrane (one of 3) that envelops the brain and spinal cord
  • Meningioma - a tumor arising in the meninges which surround the brain and spinal cord; usually slow growing and sometimes malignant
  • Meningitis - infectious disease characterized by inflammation of the meninges (the tissues that surround the brain or spinal cord) usually caused by a bacterial infection; symptoms include headache and stiff neck and fever and nausea
  • Meningocele - a congenital anomaly of the central nervous system in which a sac protruding from the brain or the spinal meninges contains cerebrospinal fluid (but no nerve tissue)
  • Meniscus - (physics) the curved upper surface of a nonturbulent liquid in a vertical tube; (optics) a lens that is concave on one side and convex on the other; (anatomy) a disk of cartilage that serves as a cushion between the ends of bones that meet at a joint
  • Menopause - the time in a woman's life in which the menstrual cycle ends
  • Menorrhagia - abnormally heavy or prolonged menstruation; can be a symptom of uterine tumors and can lead to anemia if prolonged
  • Menstrual cycle - a recurring cycle (beginning at menarche and ending at menopause) in which the endometrial lining of the uterus prepares for pregnancy; if pregnancy does not occur the lining is shed at menstruation
  • Menstruation - the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause
  • Mesothelioma - a rare form of carcinoma of the mesothelium lining lungs or abdomen or heart; usually associated with exposure to asbestos dust
  • Mesothelium - epithelium originating in the embryonic mesoderm; lines the primordial body cavity
  • Messenger RNA - the template for protein synthesis; the form of RNA that carries information from DNA in the nucleus to the ribosome sites of protein synthesis in the cell
  • Metabolic rate - rate of metabolism; the amount of energy expended in a give period
  • Metabolism - the organic processes (in a cell or organism) that are necessary for life; the marked and rapid transformation of a larva into an adult that occurs in some animals
  • Metabolite - any substance involved in metabolism (either as a product of metabolism or as necessary for metabolism)
  • Metastasis - the spreading of a disease to another part of the body; the organic processes (in a cell or organism) that are necessary for life
  • Microbe - a minute life form (especially a disease causing bacterium); the term is not in technical use
  • Microbiology - the branch of biology that studies microorganisms and their effects on humans
  • Microcephaly - an abnormally small head and underdeveloped brain
  • Microsurgery - surgery using operating microscopes and miniaturized precision instruments to perform intricate procedures on very small structures
  • Middle ear - the main cavity of the ear; between the eardrum and the inner ear
  • Midwifery - assisting women at childbirth; the branch of medicine dealing with childbirth and care of the mother
  • Migraine - a severe recurring vascular headache; occurs more frequently in women than men
  • Mineral - of or containing or derived from minerals; composed of matter other than plant or animal; relating to minerals;  solid homogeneous inorganic substances occurring in nature having a definite chemical composition
  • Miotic - of or relating to or causing constriction of the pupil of the eye;  a drug that causes miosis (constriction of the pupil of the eye)
  • Miscarriage - failure of a plan; a natural loss of the products of conception
  • Mitosis - cell division in which the nucleus divides into nuclei containing the same number of chromosomes
  • Mitral stenosis - obstruction or narrowing of the mitral valve (as by scarring from rheumatic fever)
  • Mitral valve - valve with two cusps; situated between the left atrium and the left ventricle
  • Mitral valve prolapse - cardiopathy resulting from the mitral valve not regulating the flow of blood between the left atrium and left ventricle of the heart
  • Mole - small velvety furred burrowing mammal having small eyes and fossorial forefeet; a small congenital pigmented spot on the skin; spicy sauce often containing chocolate; a protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away; a spy who works against enemy espionage; the molecular weight of a substance expressed in grams; the basic unit of amount of substance adopted under the Systeme International d'Unites
  • Molecule - (physics and chemistry) the simplest structural unit of an element or compound; (nontechnical usage) a tiny piece of anything
  • Molluscum contagiosum - a virus disease of the skin marked by round white swellings; transmitted from person to person (most often in children or in adults with impaired immune function)
  • Mononucleosis - an acute disease characterized by fever and swollen lymph nodes and an abnormal increase of mononuclear leucocytes or monocytes in the bloodstream; not highly contagious; some believe it can be transmitted by kissing
  • Morbidity - an abnormally gloomy or unhealthy state of mind; the relative incidence of a particular disease; the quality of being unhealthful and generally bad for you
  • Morning sickness - nausea early in the day; a characteristic symptom in the early months of pregnancy
  • Mortality - the quality or state of being mortal; the ratio of deaths in an area to the population of that area; expressed per 1000 per year
  • Motor nerve - a nerve that conveys impulses toward or to muscles or glands
  • MRI - the use of nuclear magnetic resonance of protons to produce proton density images
  • MS - a form of address for a woman; the form of a literary work submitted for publication; a master's degree in science; a state in the Deep South on the gulf of Mexico; one of the Confederate States during the American Civil War; a chronic progressive nervous disorder involving loss of myelin sheath around certain nerve fibers
  • Mucous membrane - mucus secreting membrane lining all body cavities or passages that communicate with the exterior
  • Mucus - protective secretion of the mucous membranes; in the gut it lubricates the passage of food and protects the epithelial cells; in the nose and throat and lungs it can make it difficult for bacteria to penetrate the body through the epithelium
  • Multiple sclerosis - a chronic progressive nervous disorder involving loss of myelin sheath around certain nerve fibers
  • Mumps - an acute contagious viral disease characterized by fever and by swelling of the parotid glands
  • Murmur - a schwa that is incidental to the pronunciation of a consonant; a complaint uttered in a low and indistinct tone; a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech; an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves; verb make complaining remarks or noises under one's breath; speak softly or indistinctly
  • Muscular dystrophy - any of several hereditary diseases of the muscular system characterized by weakness and wasting of skeletal muscles
  • Mutagen - any agent (physical or environmental) that can induce a genetic mutation or can increase the rate of mutation
  • Mutation - a change or alteration in form or qualities; (genetics) any event that changes genetic structure; any alteration in the inherited nucleic acid sequence of the genotype of an organism; (biology) an organism that has characteristics resulting from chromosomal alteration
  • Myalgia - pain in a muscle or group of muscles
  • Myasthenia gravis - a chronic progressive disease characterized by chronic fatigue and muscular weakness (especially in the face and neck); caused by a deficiency of acetylcholine at the neuromuscular junctions
  • Mycobacterium - rod shaped bacteria some saprophytic or causing diseases
  • Mycoplasma - any of a group of small parasitic bacteria that lack a cell walls and can survive without oxygen; can cause pneumonia and urinary tract infection
  • Mycosis - an inflammatory condition caused by a fungus
  • Mydriatic - a drug that causes the pupil of the eye to dilate; used to aid eye examinations
  • Myelin sheath - a layer of myelin encasing (and insulating) the axons of medullated nerve fibers
  • Myelitis - inflammation of the spinal cord
  • Myeloma - a tumor of the bone marrow (usually malignant) composed of cells normally found in bone marrow
  • Myocardial infarction - destruction of heart tissue resulting from obstruction of the blood supply to the heart muscle
  • Myocarditis - inflammation of the myocardium (the muscular tissue of the heart)
  • Myocardium - the middle muscular layer of the heart wall
  • Myopathy - any pathology of the muscles that is not attributable to nerve dysfunction
  • Myopia - (ophthalmology) eyesight abnormality resulting from the eye's faulty refractive ability; distant objects appear blurred
  • Myositis - inflammation of muscle tissue
  • Myringotomy - surgical incision into the eardrum (to relieve pressure or release pus from the middle ear)
  • Myxoma - a benign tumor of connective tissue containing jellylike material
  • Narcosis - unconsciousness induced by narcotics or anesthesia
  • Narcotic - inducing mental lethargy; inducing stupor or narcosis; of or relating to or designating narcotics;  a drug that produces numbness or stupor; often taken for pleasure or to reduce pain; extensive use can lead to addiction
  • Nasal septum - a partition of bone and cartilage between the nasal cavities
  • Nasopharynx - cavity forming the upper part of the pharynx
  • Natural childbirth - labor and childbirth without medical intervention; no drugs are given to relieve pain or aid the birth process
  • Nausea - disgust so strong it makes you feel sick; the state that precedes vomiting
  • Nebulizer - a dispenser that turns a liquid (such as perfume) into a fine mist
  • Necrosis - the localized death of living cells (as from infection or the interruption of blood supply)
  • Needle biopsy - biopsy of deep tissue that is obtained through a hollow needle
  • Neonate - a baby from birth to four weeks
  • Neoplasm - an abnormal new mass of tissue that serves no purpose
  • Nephroblastoma - malignant renal tumor of young children characterized by hypertension and blood in the urine and the presence of a palpable mass
  • Nephrosclerosis - kidney disease that is usually associated with hypertension; sclerosis of the renal arterioles reduces blood flow that can lead to kidney failure and heart failure
  • Nephrotic syndrome - a syndrome characterized by edema and large amounts of protein in the urine and usually increased blood cholesterol; usually associated with glomerulonephritis or with a complication of various systemic diseases
  • Nerve - any bundle of nerve fibers running to various organs and tissues of the body; impudent aggressiveness; the courage to carry on; verb get ready for something difficult or unpleasant
  • Nerve cell - a cell that is specialized to conduct nerve impulses
  • Nerve compression - harmful pressure on a nerve (especially in nerves that pass over rigid prominences); causes nerve damage and muscle weakness
  • Neuralgia - acute spasmodic pain along the course of one or more nerves
  • Neural tube - a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop
  • Neuritis - inflammation of a nerve accompanied by pain and sometimes loss of function
  • Neuroblastoma - malignant tumor containing embryonic nerve cells; usually metastasizes quickly
  • Neurofibromatosis - autosomal dominant disease characterized by numerous neurofibromas and by spots on the skin and often by developmental abnormalities
  • Neuroleptic - tranquilizer used to treat psychotic conditions when a calming effect is desired
  • Neuroma - any tumor derived from cells of the nervous system
  • Neuron - a cell that is specialized to conduct nerve impulses
  • Neuropathy - any pathology of the peripheral nerves
  • Neurosis - a mental or personality disturbance not attributable to any known neurological or organic dysfunction
  • Neutrophil - the chief phagocytic leukocyte; stains with either basic or acid dyes
  • Nevus - a blemish on the skin that is formed before birth
  • Niacin - a B vitamin essential for the normal function of the nervous system and the gastrointestinal tract
  • Nocturia - excessive urination at night; especially common in older men
  • Node - (computer science) any computer that is hooked up to a computer network; any bulge or swelling of an anatomical structure or part; (astronomy) a point where an orbit crosses a plane; (physics) the point of minimum displacement in a periodic system; any thickened enlargement; a connecting point at which several lines come together; the source of lymph and lymphocytes
  • Nodule - a small node; (mineralogy) a small rounded lump of mineral substance (usually harder than the surrounding rock or sediment); small rounded wartlike protuberance on a plant
  • Nondisjunction - meiosis in which there is a failure of paired homologous chromosomes to separate; results in an abnormal number of chromosomes in the daughter cells
  • Noninvasive - relating to a technique that does not involve puncturing the skin or entering a body cavity
  • Norepinephrine - a catecholamine precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses
  • NSAID - an anti inflammatory drug that does not contain steroids
  • Nucleus - a part of the cell containing DNA and RNA and responsible for growth and reproduction; any histologically identifiable mass of neural cell bodies in the brain or spinal cord; the positively charged dense center of an atom; (astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail; a small group of indispensable persons or things
  • Numbness - partial or total lack of sensation in a part of the body; a symptom of nerve damage or dysfunction; the trait of lacking enthusiasm for or interest in things generally
  • Nurse midwife - a registered nurse who has received special training as a midwife
  • Nutrient - of or providing nourishment;  any substance that can be metabolized by an organism to give energy and build tissue
  • Nystagmus - involuntary movements of the eyeballs; its presence or absence is used to diagnose a variety of neurological and visual disorders
  • Obesity - more than average fatness
  • Occlusion - (dentistry) the normal spatial relation of the teeth when the jaws are closed; closure or blockage (as of a blood vessel); the act of blocking; an obstruction in a pipe or tube; (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
  • Occupational disease - disease or disability resulting from conditions of employment (usually from long exposure to a noxious substance or from continuous repetition of certain acts)
  • Occupational therapy - physical therapy involving the therapeutic use of crafts and hobbies for the rehabilitation of handicapped or convalescing patients (especially for emotionally disturbed patients)
  • Ocular - able to be seen; relating to or using sight; of or relating to or resembling the eye;  combination of lenses at the viewing end of optical instruments
  • Oocyte - a female gametocyte that develops into an ovum after two meiotic divisions
  • Ophthalmologist - a medical doctor specializing in the treatment of diseases of the eye
  • Ophthalmoscopy - examination of the interior of an eye using an ophthalmoscope
  • Opportunistic infection - any infection caused by a microorganism that does not normally cause disease in humans; occurs in persons with abnormally functioning immune systems (as AIDS patients or transplant patients receiving immunosuppressive drugs)
  • Optic - relating to or using sight; of or relating to or resembling the eye;  the organ of sight
  • Optician - a worker who makes glasses for remedying defects of vision
  • Orbit - the (usually elliptical) path described by one celestial body in its revolution about another; the path of an electron around the nucleus of an atom; an area in which something acts or operates or has power or control: "the range of a supersonic jet"; the bony cavity in the skull containing the eyeball; a particular environment or walk of life; verb move in an orbit
  • Orchiectomy - surgical removal of one or both testicles
  • Orchiopexy - operation to bring an undescended testicle into the scrotum
  • Orchitis - inflammation of one or both testes; characterized by pain and swelling
  • Organism - a living thing that has (or can develop) the ability to act or function independently; a system considered analogous in structure or function to a living body
  • Orgasm - the moment of most intense pleasure in sexual intercourse
  • Orthopnea - form of dyspnea in which the person can breathe comfortably only when standing or sitting erect; associated with asthma and emphysema and angina pectoris
  • Osmosis - diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
  • Ossification - hardened conventionality; the developmental process of bone formation; the process of becoming rigidly fixed in a conventional pattern of thought or behavior; the calcification of soft tissue into a bonelike material
  • Osteitis - inflammation of a bone as a consequence of infection or trauma or degeneration
  • Osteitis deformans - a disease of bone occurring in the middle aged and elderly; excessive bone destruction sometimes leading to bone pain and fractures and skeletal deformities
  • Osteoarthritis - chronic breakdown of cartilage in the joints; the most common form of arthritis occurring usually after middle age
  • Osteochondroma - benign tumor containing both bone and cartilage; usually occurs near the end of a long bone
  • Osteoclast - cell that functions in the breakdown and resorption of bone tissue
  • Osteodystrophy - defective bone development; usually attributable to renal disease or to disturbances in calcium and phosphorus metabolism
  • Osteogenesis imperfecta - autosomal dominant disorder of connective tissue characterized by brittle bones that fracture easily
  • Osteolysis - lysis of bone caused by disease or infection or inadequate blood supply
  • Osteoma - a slow growing benign tumor of consisting of bone tissue; usually on the skull or mandible
  • Osteomalacia - abnormal softening of bones caused by deficiencies of phosphorus or calcium or vitamin D
  • Osteomyelitis - an inflammation of bone and bone marrow (usually caused by bacterial infection)
  • Osteopetrosis - an inherited disorder characterized by an increase in bone density; in severe forms the bone marrow cavity may be obliterated
  • Osteoporosis - abnormal loss of bony tissue resulting in fragile porous bones attributable to a lack of calcium; most common in postmenopausal women
  • Osteosarcoma - malignant bone tumor; most common in children and young adults where it tends to affect the femur
  • Otalgia - an ache localized in the middle or inner ear
  • Otitis externa - inflammation of the external ear (including auricle and ear canal)
  • Otitis media - inflammation of the middle ear; common in children
  • Otorrhea - discharge from the external ear
  • Otosclerosis - hereditary disorder in which ossification of the labyrinth of the inner ear causes tinnitus and eventual deafness
  • Ovulation - the expulsion of an ovum from the ovary (usually midway in the menstrual cycle)
  • Ovum - the female reproductive cell; the female gamete
  • Oxidation - the process of oxidizing; the addition of oxygen to a compound with a loss of electrons; always occurs accompanied by reduction
  • Oxygen - a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
  • Oxytocin - hormone secreted by the posterior pituitary gland (trade name Pitocin); stimulates contractions of the uterus and ejection of milk
  • Ozone - a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation)
  • Paget's disease - a disease of bone occurring in the middle aged and elderly; excessive bone destruction sometimes leading to bone pain and fractures and skeletal deformities
  • Palate - the upper surface of the mouth that separates the oral and nasal cavities
  • Pallor - unnatural lack of color in the skin (as from bruising or sickness or emotional distress)
  • Palpation - a method of examination in which the examiner feels the size or shape or firmness or location of something (of body parts when the examiner is a health professional)
  • Palpitation - a rapid and irregular heart beat; a shaky motion
  • Palsy - a condition marked by uncontrollable tremor; loss of the ability to move a body part; verb affect with palsy
  • Pancreas - a large elongated exocrine gland located behind the stomach; secretes pancreatic juice and insulin
  • Pancreatitis - inflammation of the pancreas; usually marked by abdominal pain
  • Pandemic - existing everywhere; epidemic over a wide geographical area;  an epidemic that is geographically widespread; occurring throughout a region or even throughout the world
  • Panic disorder - an anxiety disorder characterized by unpredictable panic attacks; the attacks are usually severe but brief
  • Papilloma - a benign epithelial tumor forming a rounded mass
  • Pap smear - a sample of secretions and superficial cells of the uterine cervix and uterus; examined with a microscope to detect any abnormal cells
  • Paracentesis - centesis of the belly to remove fluid for diagnosis
  • Paralysis - loss of the ability to move a body part
  • Paramedic - a person trained to assist medical professionals and to give emergency medical treatment
  • Paranoia - a psychological disorder characterized by delusions of persecution or grandeur
  • Paraplegia - paralysis of the lower half of the body (most often as a result of trauma)
  • Parasite - an animal or plant that lives in or on a host (another animal or plant); it obtains nourishment from the host without benefiting or killing the host; a follower who hangs around a host (without benefit to the host) in hope of gain or advantage
  • Parasympathetic nervous system - originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels
  • Parathyroid hormone - hormone synthesized and released into the blood stream by the parathyroid glands; regulates phosphorus and calcium in the body and functions in neuromuscular excitation and blood clotting
  • Parenteral - located outside the alimentary tract; administered by means other than through the alimentary tract (as by intramuscular or intravenous injection)
  • Paresis - a slight or partial paralysis
  • Paresthesia - abnormal skin sensations (as tingling or tickling or itching or burning) usually associated with peripheral nerve damage
  • Parkinson's disease - a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination
  • Paronychia - low growing annual or perennial herbs or woody plants; whitlowworts; infection in the tissues adjacent to a nail on a finger or toe
  • Paroxysm - a sudden uncontrollable attack
  • Patella - type genus of the family Patellidae: common European limpets; a small flat triangular bone in front of the knee that protects the knee joint
  • Patent - (of a bodily tube or passageway) open; affording free passage; clearly revealed to the mind or the senses or judgment;  a document granting an inventor sole rights to an invention; an official document granting a right or privilege; verb make open to sight or notice; obtain a patent for; grant rights to; grant a patent for
  • Pathogen - any disease producing agent (especially a virus or bacterium or other microorganism)
  • Pathology - the branch of medical science that studies the causes and nature and effects of diseases; any deviation from a healthy or normal condition
  • Pellagra - a disease caused by deficiency of niacin or tryptophan (or by a defect in the metabolic conversion of tryptophan to niacin); characterized by gastrointestinal disturbances and erythema and nervous or mental disorders; may be caused by malnutrition or alcoholism or other nutritional impairments
  • Pelvic inflammatory disease - inflammation of the female pelvic organs (especially the Fallopian tubes) caused by infection by any of several microorganisms (chiefly gonococci and chlamydia); symptoms are abdominal pain and fever and foul smelling vaginal discharge
  • Pelvis - a structure shaped like a funnel in the outlet of the kidney into which urine is discharged before passing into the ureter; the structure of the vertebrate skeleton supporting the lower limbs in humans and the hind limbs or corresponding parts in other vertebrates
  • Penis - the male organ of copulation (`member' is a euphemism)
  • Pepsin - an enzyme produced in the stomach that splits proteins into peptones
  • Peptic ulcer - an ulcer of the mucous membrane lining of the alimentary tract
  • Percutaneous - through the unbroken skin; refers to medications applied directly to the skin (creams or ointments) or in time release forms (skin patches)
  • Perforation - the act of punching a hole (especially a row of holes as for ease of separation); a line of small holes for tearing at a particular place; a hole made in something
  • Periarteritis nodosa - a progressive disease of connective tissue that is characterized by nodules along arteries; nodules may block the artery and result in inadequate circulation to the particular area
  • Pericardium - a serous membrane with two layers that surrounds the heart
  • Perinatal - occurring during the period around birth (5 months before and 1 month after)
  • Periosteum - a dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles; contains nerves and blood vessels that nourish the enclosed bone
  • Peristalsis - the process of wavelike muscle contractions of the alimentary tract that moves food along
  • Peritoneum - a transparent membrane that lines the abdominal cavity in mammals and covers most of the viscera
  • Pernicious anemia - a chronic progressive anemia of older adults; thought to result from a lack of intrinsic factor (a substance secreted by the stomach that is responsible for the absorption of vitamin B12)
  • Pertussis - a disease of the respiratory mucous membrane
  • Petit mal - a seizure (or a type of epilepsy characterized by such seizures) of short duration characterized by momentary unconsciousness and local muscle spasms or twitching
  • pH - (from potential of Hydrogen) the logarithm of the reciprocal of hydrogen ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is more basic and less than 7 is more acidic)
  • Phagocyte - a cell that engulfs and digests debris and invading microorganisms
  • Phantom limb - the illusion that a limb still exists after it has been amputated
  • Pharmacology - the science or study of drugs: their preparation and properties and uses and effects
  • Pharynx - the passage to the stomach and lungs; in the front part of the neck below the chin and above the collarbone
  • Phenylketonuria - a genetic disorder of metabolism; lack of the enzyme needed to turn phenylalanine into tyrosine results in an accumulation of phenylalanine in the body fluids which causes various degrees of mental deficiency
  • Pheochromocytoma - a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension
  • Phimosis - an abnormal tightness of the foreskin preventing retraction over the glans
  • Phlebitis - inflammation of a vein (usually in the legs)
  • Phlebothrombosis - thrombosis of a vein without prior inflammation of the vein; associated with sluggish blood flow (as in prolonged bedrest or pregnancy or surgery) or with rapid coagulation of the blood
  • Phlegm - expectorated matter; saliva mixed with discharges from the respiratory passages; in ancient and medieval physiology it was believed to cause sluggishness; inactivity; showing an unusual lack of energy; apathy demonstrated by an absence of emotional reactions
  • Phobia - an anxiety disorder characterized by extreme and irrational fear of simple things or social situations
  • Phosphorus - a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms; a planet (usually Venus) seen just before sunrise in the eastern sky
  • Photocoagulation - surgical procedure that uses an intense laser beam to destroy diseased retinal tissue or to make a scar that will hold the retina in cases of detached retina
  • Photophobia - a morbid fear of light; pain in the eye resulting from exposure to bright light (often associated with albinism)
  • Phototherapy - the use of strong light to treat acne or hyperbilirubinemia of the newborn
  • Physical therapy - therapy that uses physical agents: exercise and massage and other modalities
  • Physiology - processes and functions of an organism; the branch of the biological sciences dealing with the functioning of organisms
  • Pica - magpies; eating earth or clay or chalk; occurs in some primitive tribes or sometimes in cases of nutritional deficiency; a linear unit (1/6 inch) used in printing
  • PID - inflammation of the female pelvic organs (especially the Fallopian tubes) caused by infection by any of several microorganisms (chiefly gonococci and chlamydia); symptoms are abdominal pain and fever and foul smelling vaginal discharge
  • Pigmentation - coloration of living tissues by pigment; the deposition of pigment in animals or plants or human beings
  • Pinkeye - inflammation of the conjunctiva of the eye
  • Pinworm - small threadlike worm infesting human intestines and rectum especially in children
  • Pituitary gland - the master gland of the endocrine system; located at the base of the brain
  • Pityriasis alba - common form of pityriasis (usually in children or young adults) characterized by round patches of depigmentation
  • Pityriasis rosea - pityriasis in which an itchy rash develops over the trunk and extremities
  • Pivot joint - a freely moving joint in which movement is limited to rotation
  • PKU - a genetic disorder of metabolism; lack of the enzyme needed to turn phenylalanine into tyrosine results in an accumulation of phenylalanine in the body fluids which causes various degrees of mental deficiency
  • Placebo - (Roman Catholic Church) vespers of the office for the dead; an innocuous or inert medication; given as a pacifier or to the control group in experiments on the efficacy of a drug
  • Placebo effect - any effect that seems to be a consequence of administering a placebo; the change is usually beneficial and is assumed result from the person's faith in the treatment or preconceptions about what the experimental drug was supposed to do; pharmacologists were the first to talk about placebo effects but now the idea has been generalized to many situations having nothing to do with drugs
  • Placenta - the vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus; that part of the ovary of a flowering plant where the ovules form
  • Placenta previa - pregnancy in which the placenta is implanted in the lower part of the uterus (instead of the upper part); can cause bleeding late in pregnancy; delivery by cesarean section may be necessary
  • Plague - an annoyance; any large scale calamity (especially when thought to be sent by God); any epidemic disease with a high death rate; a serious (sometimes fatal) infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of a flea that has bitten an infected animal; a swarm of insects that attack plants; verb annoy continually or chronically; cause to suffer a blight
  • Plantar reflex - flexion of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front in persons over the age of 2 years; under 2 years the results should be extension of the toes (Babinski reflex)
  • Plaque - (pathology) a small abnormal patch on or inside the body; a memorial made of brass
  • Plasma - colorless watery fluid of blood and lymph containing no cells and in which erythrocytes and leukocytes and platelets are suspended; (physical chemistry) a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors; a gas becomes a plasma when it is heated until the atoms lose all their electrons, leaving a highly electrified collection of nuclei and free electrons; a green slightly translucent variety of chalcedony used as a gemstone
  • Plasma cell - a cell that develops from a B lymphocyte in reaction to a specific antigen; found in bone marrow and sometimes in the blood
  • Plasmapheresis - plasma is separated from whole blood and the rest is returned to the donor
  • Platelet - tiny bits of protoplasm found in vertebrate blood; essential for blood clotting
  • Pleura - the thin serous membrane around the lungs and inner walls of the chest
  • Pleural space - the small potential space between the parietal and visceral layers of the pleura
  • Pleurisy - inflammation of the pleura of the lungs (especially the parietal layer)
  • Pleurodynia - pain in the chest caused by inflammation of the muscles between the ribs
  • PMS - a syndrome that occurs in many women from 2 to 14 days before the onset of menstruation
  • Pneumoconiosis - chronic respiratory disease caused by inhaling metallic or mineral particles
  • Pneumonectomy - surgical removal of a lung (usually to treat lung cancer)
  • Pneumonia - respiratory disease characterized by inflammation of the lung parenchyma (excluding the bronchi) with congestion caused by viruses or bacteria or irritants
  • Pneumothorax - abnormal presence of air in the pleural cavity resulting in the collapse of the lung; may be spontaneous (due to injury to the chest) or induced (as a treatment for tuberculosis)
  • Poliomyelitis - an acute viral disease marked by inflammation of nerve cells of the brain stem and spinal cord
  • Polycystic kidney disease - kidney disease characterized by enlarged kidneys containing many cysts; often leads to kidney failure
  • Polycythemia - a disorder characterized by an abnormal increase in the number of red blood cells in the blood
  • Polydactyly - birth defect characterized by the presence of more than the normal number of fingers or toes
  • Polydipsia - excessive thirst (as in cases of diabetes or kidney dysfunction)
  • Polymyositis - myositis characterized by weakness of limb and neck muscles and much muscle pain and swelling; progression and severity vary among individuals
  • Polyp - one of two forms that coelenterates take e.g. a hydra or coral: usually sedentary and has a hollow cylindrical body usually with a ring of tentacles around the mouth; a small vascular growth on the surface of a mucous membrane
  • Polysaccharide - any of a class of carbohydrates whose molecules contain chains of monosaccharide molecules
  • Polyunsaturated fat - a class of fats having long carbon chains with many double bonds unsaturated with hydrogen atoms; used in some margarines; supposedly associated with low blood cholesterol
  • Polyuria - renal disorder characterized by the production of large volumes of pale dilute urine; often associated with diabetes
  • Porphyria - a genetic abnormality of metabolism causing abdominal pains and mental confusion
  • Portal hypertension - increase in blood pressure in the veins of the portal system caused by obstruction in the liver (often associated with alcoholic cirrhosis), causing enlargement of the spleen and collateral veins
  • Portal vein - a short vein that carries blood into the liver
  • Posterior - at or near the hind end in quadrupeds or toward the spine in primates;  a tooth situated at the back of the mouth; the fleshy part of the human body that you sit on
  • Postmortem examination - an examination and dissection of a dead body to determine cause of death or the changes produced by disease
  • Postnatal - occurring immediately after birth
  • Potassium - a light soft silver white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite
  • Precancerous - of or relating to a growth that is not malignant but is likely to become so if not treated
  • Preeclampsia - abnormal state of pregnancy characterized by hypertension and fluid retention and albuminuria; can lead to eclampsia if untreated
  • Premenstrual syndrome - a syndrome that occurs in many women from 2 to 14 days before the onset of menstruation
  • Prenatal diagnosis - any of the diagnostic procedures used to determine whether a fetus has a genetic abnormality
  • Prepuce - a fold of skin covering the tip of the penis; a fold of skin covering the tip of the clitoris
  • Presbyopia - farsightedness resulting from a reduced ability to focus caused by loss of elasticity of the crystalline lens with age
  • Pressure point - any of several points on the body where the pulse can be felt and where pressure on an underlying artery will control bleeding from that artery at a more distal point
  • Pressure sore - a chronic ulcer of the skin caused by prolonged pressure on it (as in bedridden patients)
  • Priapism - condition in which the penis is continually erect; usually painful and seldom with sexual arousal
  • Prickly heat - obstruction of the sweat ducts during high heat and humidity
  • Primary - not derived from or reducible to something else; basic; of first rank or importance or value; direct and immediate rather than secondhand; of primary importance; most important element; of or being the essential or basic part;  a preliminary election where delegates or nominees are chosen; one of the main flight feathers projecting along the outer edge of a bird's wing; coil forming the part of an electrical circuit such that changing current in it induces a current in a neighboring circuit
  • Prion - (microbiology) an infectious protein particle similar to a virus but lacking nucleic acid; thought to be the agent responsible for scrapie and other degenerative diseases of the nervous system
  • Proctitis - inflammation of the rectum; marked by bloody stools and a frequent urge to defecate; frequently associated with Crohn's disease or ulcerative colitis
  • Proctoscopy - visual examination of the rectum and the end of the colon by means of a proctoscope
  • Progeria - a rare abnormality marked by premature aging (grey hair and wrinkled skin and stooped posture) in a child
  • Progesterone - a steroid hormone (trade name Lipo Lutin) produced in the ovary; prepares and maintains the uterus for pregnancy
  • Prognosis - a prediction of the course of a disease; a prediction about how something (as the weather) will develop
  • Prolactin - gonadotropic hormone secreted by the anterior pituitary; in females it stimulates growth of the mammary glands and lactation after parturition
  • Prolapse - the slipping or falling out of place of an organ (as the uterus); verb slip or fall out of place, as of body parts
  • Prophylactic - preventing or contributing to the prevention of disease; tending to ward off; capable of preventing conception or impregnation;  contraceptive device consisting of a sheath of thin rubber or latex that is worn over the penis during intercourse; remedy that prevents or slows the course of an illness or disease
  • Proprioception - the ability to sense the position and location and orientation and movement of the body and its parts
  • Prostatectomy - surgical removal of part or all of the prostate gland
  • Prostate gland - a firm partly muscular chestnut sized gland in males at the neck of the urethra; produces a viscid secretion that is the fluid part of semen
  • Prostatitis - inflammation of the prostate gland characterized by perineal pain and irregular urination and (if severe) chills and fever
  • Prosthesis - corrective consisting of a replacement for a part of the body
  • Proto oncogene - a normal gene that has the potential to become an oncogene
  • Protozoan - of or relating to the Protozoa;  any of diverse minute acellular or unicellular organisms usually nonphotosynthetic
  • Proximal - situated nearest to point of attachment or origin
  • Pruritus - an intense itching sensation that can have various causes (as by allergies or infection or lymphoma or jaundice etc.)
  • Psittacosis - an atypical pneumonia caused by a rickettsia microorganism and transmitted to humans from infected birds; infectious disease of birds
  • Psoriasis - a chronic skin disease characterized by dry red patches covered with scales; occurs especially on the scalp and ears and genitalia and the skin over bony prominences
  • Psoriatic arthritis - a form of rheumatoid arthritis usually affecting fingers and toes and associated with psoriasis
  • Psychogenic - mental or emotional rather than physiological in origin; of or relating to the psychological cause of a disorder
  • Psychological - mental or emotional as opposed to physical in nature; of or relating to or determined by psychology
  • Psychosis - any severe mental disorder in which contact with reality is lost or highly distorted
  • Psychosomatic - used of illness or symptoms resulting from neurosis
  • Psychotherapy - the treatment of mental or emotional problems by psychological means; the branch of psychiatry concerned with psychological methods
  • Psychotic - characteristic of or suffering from psychosis;  a person afflicted with psychosis
  • Ptosis - drooping of the upper eyelid caused by muscle paralysis and weakness
  • Puberty - the time of life when sex glands become functional
  • Pubic louse - infests the pubic region of the human body
  • Pudendal block - regional anesthesia resulting from the use of a local anesthetic to deaden the pudendal nerves in the region of the vulva and labia majora; used to ease discomfort during childbirth
  • Pudendum - human external genital organs collectively especially of a female
  • Puerperium - time period following childbirth when the mother's uterus shrinks and the other functional and anatomic changes of pregnancy are resolved
  • Pulmonary artery - one of two arteries (branches of the pulmonary trunk) that carry venous blood from the heart to the lungs
  • Pulmonary embolism - blockage of the pulmonary artery by foreign matter or by a blood clot
  • Pulmonary stenosis - abnormal narrowing of the opening into the pulmonary artery from the right ventricle
  • Pulp - the soft inner part of a tooth; an inexpensive magazine printed on poor quality paper; any soft or soggy mass; a soft moist part of a fruit; a mixture of cellulose fibers; verb reduce to pulp; remove the pulp from, as from a fruit
  • Pulse - the rhythmic contraction and expansion of the arteries with each beat of the heart; edible seeds of various pod bearing plants (peas or beans or lentils etc.); the rate at which the heart beats; usually measured to obtain a quick evaluation of a person's health; (electronics) a sharp transient wave in the normal electrical state (or a series of such transients); verb produce or modulate (as electromagnetic waves) in the form of short bursts or pulses or cause an apparatus to produce pulses; drive by or as if by pulsation; expand and contract rhythmically; beat rhythmically
  • Pupil - contractile aperture in the iris of the eye; a young person attending school (up through senior high school); a learner who is enrolled in an educational institution
  • Pus - a fluid product of inflammation; the tenth month of the Hindu calendar
  • Pustule - a small inflamed elevation of skin containing pus; a blister filled with pus
  • Pyelonephritis - inflammation of the kidney and its pelvis caused by bacterial infection
  • Pyloric sphincter - the sphincter muscle of the pylorus that separates the stomach from the duodenum
  • Pyloric stenosis - narrowing of the pyloric sphincter that blocks the passage of food from the stomach into the duodenum
  • Pyrexia - a rise in the temperature of the body; frequently a symptom of infection
  • Pyrogen - any substance that can cause a rise in body temperature; any substance characterized by its great flammability
  • Pyuria - presence of white blood cells in the urine; symptom of urinary tract infection
  • Radial keratotomy - radial pattern of incisions in the cornea that cause the cornea to bulge; performed to correct myopia
  • Radiation - the act of spreading outward from a central source; a radial arrangement of nerve fibers connecting different parts of the brain; the spread of a group of organisms into new habitats; energy that is radiated or transmitted in the form of rays or waves or particles; the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay; (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance; syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours
  • Radiation therapy - (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance
  • Radiography - photography that uses other kinds of radiation than visible light; the process of making a radiograph; producing an image on a radiosensitive surface by radiation other than visible light
  • Radius - the length of a line segment between the center and circumference of a circle or sphere; the outer and slightly shorter of the two bones of the human forearm; a circular region whose area is indicated by the length of its radius; a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere); support consisting of a radial member of a wheel joining the hub to the rim
  • Radon - a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
  • Rash - imprudently incurring risk; marked by defiant disregard for danger or consequences;  a series of unexpected and unpleasant occurrences; any red eruption of the skin
  • Receptor - a cellular structure that is postulated to exist in order to mediate between a chemical agent that acts on nervous tissue and the physiological response; an organ having nerve endings (in the skin or viscera or eye or ear or nose or mouth) that respond to stimulation
  • Recessive gene - gene that produces its characteristic phenotype only when its allele is identical
  • Rectum - the terminal section of the alimentary canal; from the sigmoid flexure to the anus
  • Red blood cell - a mature blood cell that contains hemoglobin to carry oxygen to the bodily tissues; a biconcave disc that has no nucleus
  • Referred pain - pain that is felt at a place in the body different from the injured or diseased part where the pain would be expected
  • Reflex - without volition or conscious control;  an automatic instinctive unlearned reaction to a stimulus
  • Regurgitation - recall after rote memorization; backflow of blood through a defective heart valve; the reflex act of ejecting the contents of the stomach through the mouth
  • Rehabilitation - the restoration of someone to a useful place in society; the treatment of physical disabilities by massage and electrotherapy and exercises; vindication of a person's character and the re establishment of that person's reputation; the conversion of wasteland into land suitable for use of habitation or cultivation
  • Reiter's syndrome - an inflammatory syndrome (etiology unknown) predominantly in males; characterized by arthritis and conjunctivitis and urethritis
  • Relapse - a failure to maintain a higher state; verb go back to bad behavior; deteriorate in health
  • Remission - (law) the act of remitting (especially the referral of a law case to another court); an abatement in intensity or degree (as in the manifestations of a disease); the act of absolving or remitting; formal redemption as proced by a priest in the sacrament of penance; a payment of money sent to a person in another place
  • REM sleep - a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep
  • Renal colic - sharp pain in the lower back that radiates into the groin; associated with the passage of a renal calculus through the ureter
  • Renin - a proteolytic enzyme secreted by the kidneys; catalyzes the formation of angiotensin and thus affects blood pressure
  • Reproductive system - organs and tissues involved in the production and maturation of gametes and in their union and subsequent development as offspring
  • Resection - surgical removal of part of a structure or organ
  • Respiration - the metabolic processes whereby certain organisms obtain energy from organic molecules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs; a single complete act of breathing in and out; the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation
  • Respirator - a breathing device for administering long term artificial respiration; a protective mask with a filter; protects the face and lungs against poisonous gases
  • Respiratory distress syndrome - an acute lung disease of the newborn (especially the premature newborn); lungs cannot expand because of a wetting agent is lacking; characterized by rapid shallow breathing and cyanosis and the formation of a glassy hyaline membrane over the alveoli
  • Respiratory system - the system for taking in oxygen and giving off carbon dioxide; in terrestrial animals this is accomplished by breathing
  • Reticulocyte - an immature red blood cell containing a network of filaments or granules
  • Retina - the light sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve
  • Retinoblastoma - malignant ocular tumor of retinal cells; usually occurs before the third year of life; composed of primitive small round retinal cells
  • Reye's syndrome - acquired brain disorder following acute viral infections (especially influenza or chicken pox) in young children
  • Rheumatic fever - a severe disease chiefly of children and characterized by painful inflammation of the joints and frequently damage to the heart valves
  • Rheumatoid arthritis - a chronic autoimmune disease with inflammation of the joints and marked deformities; something (possibly a virus) triggers an attack on the synovium by the immune system, which releases cytokines that stimulate an inflammatory reaction that can lead to the destruction of all components of the joint
  • Rh incompatibility - incompatibility of Rh blood types; a transfusion of Rh positive blood given to a Rh negative person (or vice versa) can result in hemolysis and anemia
  • Rhinitis - an inflammation of the mucous membrane lining the nose (usually associated with nasal discharge)
  • Rhinophyma - enlargement of the nose with dilation of follicles and redness and prominent vascularity of the skin; often associated with excessive consumption of alcohol
  • Rhinoplasty - cosmetic surgery to improve the appearance of your nose
  • Rhythm method - natural family planning in which ovulation is assumed to occur 14 days before the onset of a period (the fertile period would be assumed to extend from day 10 through day 18 of her cycle)
  • Riboflavin - a B vitamin that prevents skin lesions and weight loss
  • Rickets - childhood disease caused by deficiency of vitamin D and sunlight associated with impaired metabolism of calcium and phosphorus
  • Rigor mortis - muscular stiffening that begins 2 to 4 hours after death and last for about 4 days; temporary stiffness of joints and muscular rigidity occurring after death
  • Ringworm - infections of the skin or nails caused by fungi and appearing as itching circular patches
  • RNA - (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell
  • Rosacea - a skin disease of adults (more often women) in which blood vessels of the face enlarge resulting in a flushed appearance
  • Roseola infantum - a viral disease of infants and young children; characterized by abrupt high fever and mild sore throat; a few days later there is a faint pinkish rash that lasts for a few hours to a few days
  • Rotator cuff - a supporting structure of the shoulder consisting of the muscles and tendons that attach the arm to the shoulder joint and enable the arm to move
  • Roundworm - unsegmented worms with elongated rounded body pointed at both ends; mostly free living but some are parasitic; infections of the skin or nails caused by fungi and appearing as itching circular patches
  • Rubella - a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester
  • Rubeola - an acute and highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children
  • Rupture - the act of making a sudden noisy break; a personal or social separation (as between opposing factions); state of being torn or burst open; verb separate or cause to separate abruptly
  • Sacrum - wedge shaped bone consisting of five fused vertebrae forming the posterior part of the pelvis; its base connects with the lowest lumbar vertebra and its tip with the coccyx
  • Safe sex - sexual activity (especially sexual intercourse) with the use of measures (such as latex condoms) to avoid the transmission of disease (especially AIDS)
  • Saline - containing salt;  an isotonic solution of sodium chloride and distilled water
  • Salmonella - rod shaped Gram negative enterobacteria; cause typhoid fever and food poisoning; can be used as a bioweapon
  • Salmonellosis - a kind of food poisoning caused by eating foods contaminated with Salmonella typhimurium
  • Salpingitis - inflammation of a Fallopian tube (usually the result of infection spreading from the vagina or uterus) or of a Eustachian tube
  • Sarcoidosis - a chronic disease of unknown cause marked by the formation of nodules in the lungs and liver and lymph glands and salivary glands
  • Sarcoma - a usually malignant tumor arising from connective tissue (bone or muscle etc.); one of the four major types of cancer
  • Scabies - a contagious skin infection caused by the itch mite; characterized by persistent itching and skin irritation
  • Scarlet fever - an acute communicable disease (usually in children) characterized by fever and a red rash
  • Schistosomiasis - an infestation with or a resulting infection caused by a parasite of the genus Schistosoma; common in the tropics and Far East; symptoms depend on the part of the body infected
  • Schizophrenia - any of several psychotic disorders characterized by distortions of reality and disturbances of thought and language and withdrawal from social contact
  • Sciatica - neuralgia along the sciatic nerve
  • Sclera - whitish fibrous membrane (albuginea) that with the cornea forms the outer covering of the eyeball
  • Scleroderma - genus of poisonous fungi having hard skinned fruiting bodies: false truffles; an autoimmune disease that affects the blood vessels and connective tissue; fibrous connective tissue is deposited in the skin
  • Scoliosis - an abnormal lateral curve to the vertebral column
  • Screening - testing objects or persons in order to identify those with particular characteristics; fabric of metal or plastic mesh; the display of a motion picture; the act of concealing the existence of something by obstructing the view of it
  • Scrotum - the external pouch that contains the testes
  • Scurvy - of the most contemptible kind;  a condition caused by deficiency of ascorbic acid (vitamin C)
  • Sebaceous cyst - a common cyst of the skin; filled with fatty matter (sebum) that is secreted by a sebaceous gland that has been blocked
  • Seborrhea - a condition in which overactivity of the sebaceous glands causes the skin to become oily
  • Sebum - the oily secretion of the sebaceous glands; with perspiration it moistens and protects the skin
  • Secondary - belonging to a lower class or rank; not of major importance; being of second rank or importance or value; not direct or immediate; depending on or incidental to what is original or primary; inferior in rank or status;  the defensive football players who line up behind the linemen; coil such that current is induced in it by passing a current through the primary coil
  • Seizure - the taking possession of something by legal process; a sudden occurrence (or recurrence) of a disease; the act of forcibly dispossessing an owner of property; the act of taking of a person by force
  • Selenium - a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite)
  • Semen - the thick white fluid containing spermatozoa that is ejaculated by the male genital tract
  • Seminoma - malignant tumor of the testis; usually occurring in older men
  • Sensory nerve - a nerve that passes impulses from receptors toward or to the central nervous system
  • Sepsis - the presence of pus forming bacteria or their toxins in the blood or tissues
  • Septal defect - a congenital abnormality in the septum between the left and right sides of the heart
  • Septicemia - invasion of the bloodstream by virulent microorganisms from a focus of infection
  • Serotonin - a neurotransmitter involved in e.g. sleep and depression and memory
  • Serum - watery fluid of the blood that resembles plasma but contains fibrinogen
  • Shigellosis - an acute infection of the intestine by shigella bacteria; characterized by diarrhea and fever and abdominal pains
  • Shingles - eruptions along a nerve path often accompanied by severe neuralgia
  • Shin splints - painful inflammation of the muscles around the shins; frequent among runners
  • Shock - the violent interaction of individuals or groups entering into combat; an unpleasant or disappointing surprise; an instance of agitation of the earth's crust; a bushy thick mass (especially hair); a pile of sheaves of grain set on end in a field to dry; stalks of Indian corn set up in a field; (pathology) bodily collapse or near collapse caused by inadequate oxygen delivery to the cells; characterized by reduced cardiac output and rapid heartbeat and circulatory insufficiency and pallor; a reflex response to the passage of electric current through the body; a mechanical damper; absorbs energy of sudden impulses; the feeling of distress and disbelief that you have when something bad happens accidentally; verb subject to electrical shocks; collect or gather into shocks; collide violently; strike with horror or terror; surprise greatly; knock someone's socks off; strike with disgust or revulsion; inflict a trauma upon
  • Shunt - implant consisting of a tube made of plastic or rubber; for draining fluids within the body; a conductor having low resistance in parallel with another device to divert a fraction of the current; a passage by which a bodily fluid (especially blood) is diverted from one channel to another; verb transfer to another track, of trains; provide with or divert by means of an electrical shunt
  • SIDS - sudden and unexpected death of an apparently healthy infant during sleep
  • Sigmoidoscopy - visual examination (with a sigmoidoscope) of the lower third of the colon in a search for polyps
  • Silicone - any of a large class of siloxanes that are unusually stable over a wide range of temperatures; used in lubricants and adhesives and coatings and synthetic rubber and electrical insulation
  • Silicosis - a lung disease caused by inhaling particles of silica or quartz or slate
  • Sinoatrial node - a specialized bit of heart tissue that controls the heartbeat
  • Sinus - any of various air filled cavities especially in the bones of the skull; a wide channel containing blood; does not have the coating of an ordinary blood vessel; an abnormal passage leading from a suppurating cavity to the body surface
  • Sinusitis - inflammation of one of the paranasal sinuses
  • Skin graft - a piece of skin taken from a donor area and surgically grafted at the site of an injury or burn
  • Skin patch - a medicated adhesive pad placed on the skin for absorption of a time released dose of medication into the bloodstream
  • Skull - the bony skeleton of the head of vertebrates
  • Sleeping sickness - an encephalitis that was epidemic between 1915 and 1926; symptoms include paralysis of the extrinsic eye muscle and extreme muscular weakness
  • Small cell carcinoma - highly malignant carcinoma composed of small round or egg shaped cells with little cytoplasm; lung cancers are frequently oat cell carcinomas
  • Small intestine - the longest part of the alimentary canal; where digestion is completed
  • Smallpox - a highly contagious viral disease characterized by fever and weakness and skin eruption with pustules that form scabs that slough off leaving scars
  • Smear - a thin tissue or blood sample spread on a glass slide and stained for cytologic examination and diagnosis under a microscope; slanderous defamation; an act that brings discredit to the person who does it; a blemish made by dirt; verb make a smudge on; soil by smudging; stain by smearing or daubing with a dirty substance; charge falsely or with malicious intent; attack the good name and reputation of someone; cover (a surface) by smearing (a substance) over it
  • Sodium - a silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in sea water and in the mineral halite (rock salt)
  • Sodium bicarbonate - a white soluble compound (NaHCO3) used in effervescent drinks and in baking powders and as an antacid
  • Solar plexus - a large plexus of sympathetic nerves in the abdomen behind the stomach
  • Somatic - affecting or characteristic of the body as opposed to the mind or spirit
  • Spasm - (pathology) sudden constriction of a hollow organ (as a blood vessel); a painful and involuntary muscular contraction
  • Spasticity - the quality of moving or acting in spasms
  • Spastic paralysis - a loss or deficiency of motor control with involuntary spasms caused by permanent brain damage present at birth
  • Speculum - a medical instrument for dilating a bodily passage or cavity in order to examine the interior; a mirror (especially one made of polished metal) for use in an optical instrument
  • Sperm - the male reproductive cell; the male gamete
  • Spermatocele - a swelling on the epididymis or the testis; usually contains spermatozoa
  • Sperm count - the act of estimating the number of spermatozoa in an ejaculate; the number of sperm in an ejaculate
  • Spermicide - a contraceptive agent that kills spermatozoa
  • Sphincter - a ring of muscle that contracts to close an opening
  • Spider nevus - a dilation of superficial capillaries with a central red dot from which blood vessels radiate
  • Spina bifida - a not uncommon congenital defect in which a vertebra is malformed; unless several vertebrae are affected or there is myelomeningocele there are few symptoms; can be diagnosed by amniocentesis
  • Spinal cord - a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tubelike structure extending from the base of the brain through the vertebral canal to the upper lumbar region
  • Spinal fusion - correction of an unstable part of the spine by joining two or more vertebrae; usually done surgically but sometimes done by traction or immobilization
  • Spinal tap - removal by centesis of fluid from the subarachnoid space of the lumbar region of the spinal cord for diagnostic or therapeutic purposes
  • Spine - a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin; the part of a book's cover that encloses the inner side of the book's pages and that faces outward when the book is shelved; a small sharp pointed tip resembling a spike on a stem or leaf; the series of vertebrae forming the axis of the skeleton and protecting the spinal cord; any sharply pointed projection
  • Spirometry - the use of a spirometer to measure vital capacity
  • Spleen - a large dark red oval organ on the left side of the body between the stomach and the diaphragm; produces cells involved in immune responses; a feeling of resentful anger
  • Splint - an orthopedic mechanical device used to immobilize and protect a part of the body (as a broken leg); a thin sliver of wood; verb support with a splint
  • Spondylitis - inflammation of a spinal joint; characterized by pain and stiffness
  • Spondylolisthesis - a forward dislocation of one vertebra over the one beneath it producing pressure on spinal nerves
  • Sporotrichosis - a chronic fungal infection of the skin and lymph nodes
  • Sprain - a painful injury to a joint caused by a sudden wrenching of its ligaments; verb twist suddenly so as to sprain
  • Sprue - a chronic disorder that occurs in tropical and non tropical forms and in both children and adults; nutrients are not absorbed; symptoms include foul smelling diarrhea and emaciation
  • Sputum - expectorated matter; saliva mixed with discharges from the respiratory passages; in ancient and medieval physiology it was believed to cause sluggishness
  • Stapedectomy - surgical removal of the stapes of the middle ear
  • Staphylococci - spherical Gram positive parasitic bacteria that tend to form irregular colonies; some cause boils or septicemia or infections
  • Status asthmaticus - a prolonged and severe asthma attack that does not respond to standard treatment
  • Status epilepticus - a condition in which there are continuing attacks of epilepsy without intervals of consciousness; can lead to brain damage and death
  • Stenosis - abnormal narrowing of a bodily canal or passageway
  • Stent - a slender tube inserted inside a tubular body part (as a blood vessel) to provide support during and after surgical anastomosis
  • Sterilization - the procedure of making some object free of live bacteria or other microorganisms (usually by heat or chemical means); the act of making an organism barren or infertile (unable to reproduce)
  • Sternum - the flat bone that articulates with the clavicles and the first seven pairs of ribs
  • Stillbirth - a natural loss of the products of conception
  • Stoma - a mouth or mouthlike opening (especially one created by surgery on the surface of the body to create an opening to an internal organ); a minute epidermal pore in a leaf or stem through which gases and water vapor can pass
  • Stool - a simple seat without a back or arms; (forestry) the stump of a tree that has been felled or headed for the production of saplings; a plumbing fixture for defecation and urination; solid excretory product evacuated from the bowels; verb have a bowel movement; grow shoots in the form of stools or tillers; react to a decoy, of wildfowl; lure with a stool, as of wild fowl
  • Strabismus - abnormal alignment of one or both eyes
  • Strain - an intense or violent exertion; (physics) deformation of a physical body under the action of applied forces; injury to a muscle (often caused by overuse); results in swelling and pain; (psychology) nervousness resulting from mental stress; the act of singing; an effortful attempt to attain a goal; a lineage or race of people; the general meaning or substance of an utterance; a succession of notes forming a distinctive sequence; a special variety of domesticated animals within a species; (biology) a group of organisms within a species that differ in trivial ways from similar groups; difficulty that causes worry or emotional tension; verb use to the utmost; exert vigorously or to full capacity; become stretched or tense or taught; cause to be tense and uneasy or nervous or anxious; alter the shape of (something) by stress; to exert much effort or energy; rub through a strainer or process in an electric blender; remove by passing through a filter; separate by passing through a sieve or other straining device to separate out coarser elements; test the limits of
  • Strep throat - an infection of the oral pharynx and tonsils by streptococcus
  • Streptococci - spherical Gram positive bacteria occurring in pairs or chains; cause e.g. scarlet fever and tonsillitis
  • Stress fracture - fracture resulting from excessive activity rather than a specific injury
  • Stroke - a light touch with the hands; a single complete movement; (sports) the act of swinging or striking at a ball with a club or racket or bat or cue or hand; any one of the repeated movements of the limbs and body used for locomotion in swimming or rowing; a mark made by a writing implement (as in cursive writing); a light touch; the oarsman nearest the stern of the shell who sets the pace for the rest of the crew; a sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in the brain; a punctuation mark (/) used to separate related items of information; the maximum movement available to a pivoted or reciprocating piece by a cam; verb treat gingerly or carefully; strike a ball with a smooth blow; row at a particular rate; touch lightly and with affection, with brushing motions
  • Stye - an infection of the sebaceous gland of the eyelid
  • Submucosa - the connective tissue beneath mucous membrane
  • Suppository - a small plug of medication designed for insertion into the rectum or vagina where it melts
  • Suppuration - a fluid product of inflammation; (medicine) the formation of morbific matter in an abscess or a vesicle and the discharge of pus
  • Surfactant - a substance capable of reducing the surface tension of a liquid in which it is dissolved
  • Surrogate - providing or receiving nurture or parental care though not related by blood or legal ties;  someone who takes the place of another person; a person appointed to represent or act on behalf of others
  • Suture - thread of catgut or silk or wire used by surgeons to stitch tissues together; a seam used in surgery; an immovable joint (especially between the bones of the skull); verb join with a suture
  • Sympathetic nervous system - originates in the thoracic regions of the spinal cord; opposes physiological effects of the parasympathetic: reduces digestive secretions; speeds the heart; contracts blood vessels
  • Syndactyly - birth defect in which there is partial or total webbing connecting two or more fingers or toes
  • Syndrome - a complex of concurrent things; a pattern of symptoms indicative of some disease
  • Synovial fluid - viscid lubricating fluid secreted by the membrane lining joints and tendon sheaths etc.
  • Synovial membrane - a thin membrane in synovial (freely moving) joints that lines the joint capsule and secretes synovial fluid
  • Syphilis - a common venereal disease caused by the treponema pallidum spirochete; symptoms change through progressive stages; can be congenital (transmitted through the placenta)
  • Systemic lupus erythematosus - an inflammatory disease of connective tissue with variable features including fever and weakness and fatigability and joint pains and skin lesions on the face or neck or arms
  • Systolic pressure - the blood pressure (as measured by a sphygmomanometer) during the contraction of the left ventricle of the heart
  • Tapeworm - ribbonlike flatworms that are parasitic in the intestines of humans and other vertebrates
  • Tar - a man who serves as a sailor; any of various dark heavy viscid substances obtained as a residue; verb coat with tar
  • Tartar - an incrustation that forms on the teeth and gums; a member of the Mongolian people of central Asia who invaded Russia in the 13th century; a fiercely vigilant and unpleasant woman; a salt used especially in baking powder
  • TB - a unit of information equal to a trillion (1,099,511,627,776) bytes or 1024 gigabytes; infection transmitted by inhalation or ingestion of tubercle bacilli and manifested in fever and small lesions (usually in the lungs but in various other parts of the body in acute stages); a metallic element of the rare earth group; used in lasers; occurs in apatite and monazite and xenotime and ytterbite
  • T cell - a small lymphocyte developed in the thymus; it orchestrates the immune system's response to infected or malignant cells
  • Tear duct - any of several small ducts that carry tears from the lacrimal glands
  • Temporal arteritis - inflammation of the temporal arteries; characterized by headaches and difficulty chewing and (sometimes) visual impairment
  • Tendon - a cord or band of inelastic tissue connecting a muscle with its bony attachment
  • Tennis elbow - painful inflammation of the tendon at the outer border of the elbow resulting from overuse of lower arm muscles (as in twisting of the hand)
  • Tenosynovitis - inflammation of a tendon and its enveloping sheath
  • Tension headache - a headache located at the back of the head; usually caused by body tension resulting from overwork or psychological stress
  • Teratogen - any agent that interferes with normal embryonic development: alcohol or thalidomide or X rays or rubella are examples
  • Teratoma - a tumor consisting of a mixture of tissues not normally found at that site
  • Testosterone - a potent androgenic hormone produced chiefly by the testes; responsible for the development of male secondary sex characteristics
  • Tetanus - a sustained muscular contraction resulting from a rapid series of nerve impulses; an acute and serious infection of the central nervous system caused by bacterial infection of open wounds; spasms of the jaw and laryngeal muscles may occur during the late stages
  • Tetralogy of Fallot - a congenital heart defect producing cyanosis; characterized by four symptoms: pulmonary stenosis and ventricular septal defect and malposition of the aorta over both ventricles and hypertrophy of the right ventricle
  • Thalamus - large egg shaped structures of grey matter that form the dorsal subdivision of the diencephalon
  • Thalassemia - an inherited form of anemia caused by faulty synthesis of hemoglobin
  • Thoracotomy - surgical incision into the chest walls opening up the pleural cavity
  • Thorax - part of an insect's body that bears the wings and legs; the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates; the middle region of the body of an arthropod between the head and the abdomen
  • Thrill - something that causes you to experience a sudden intense feeling or sensation; an almost pleasurable sensation of fright; the swift release of a store of affective force; verb feel sudden intense sensation or emotion; cause to be thrilled by some perceptual input; fill with sublime emotion; tickle pink; tremble convulsively, as from fear or excitement
  • Thrombectomy - surgical removal of a blood clot (thrombus) from a blood vessel
  • Thrombocytopenic purpura - purpura associated with a reduction in circulating blood platelets which can result from a variety of factors
  • Thromboembolism - occlusion of a blood vessel by an embolus that has broken away from a thrombus
  • Thrombophlebitis - phlebitis in conjunction with the formation of a blood clot (thrombus)
  • Thrombosis - the formation or presence of a thrombus (a clot of coagulated blood attached at the site of its formation) in a blood vessel
  • Thrombus - a blood clot formed within a blood vessel and remaining attached to its place of origin
  • Thrush - songbirds characteristically having brownish upper plumage with a spotted breast; a woman who sings popular songs; candidiasis of the oral cavity; seen mostly in infants or debilitated adults
  • Thymus gland - a ductless glandular organ at the base of the neck that produces lymphocytes and aids in producing immunity; atrophies with age
  • Thyrotoxicosis - an overactive thyroid gland; pathologically excessive production of thyroid hormones or the condition resulting from excessive production of thyroid hormones
  • Thyroxin - hormone produced by the thyroid glands to regulate metabolism by controlling the rate of oxidation in cells
  • TIA - brief episode in which the brain gets insufficient blood supply; symptoms depend on the site of the blockage
  • Tibia - the inner and thicker of the two bones of the human leg between the knee and ankle
  • Tic - a local and habitual twitching especially in the face
  • Tic douloureux - intense paroxysmal neuralgia along the trigeminal nerve
  • Tietze's syndrome - syndrome characterized by swelling of rib cartilage (causing pain)
  • Tinea - type genus of the Tineidae: clothes moths; infections of the skin or nails caused by fungi and appearing as itching circular patches
  • Tinnitus - a ringing or booming sensation in one or both ears; a symptom of an ear infection or Meniere's disease
  • Tissue plasminogen activator - a thrombolytic agent (trade name Activase) that causes fibrinolysis at the site of a blood clot; used in treating acute myocardial infarction
  • Tissue typing - a series of diagnostic tests before an organ transplant to determine whether the tissues of a donor and recipient are compatible
  • T lymphocyte - a small lymphocyte developed in the thymus; it orchestrates the immune system's response to infected or malignant cells
  • Tolerance - the act of tolerating something; the power or capacity of an organism to tolerate unfavorable environmental conditions; willingness to recognize and respect the beliefs or practices of others; a disposition to allow freedom of choice and behavior; a permissible difference; allowing some freedom to move within limits
  • Tonsillectomy - surgical removal of the palatine tonsils; commonly performed along with adenoidectomy
  • Tonsillitis - inflammation of the tonsils (especially the palatine tonsils)
  • Tourette's syndrome - neurological disorder characterized by facial grimaces and tics and movements of the upper body and grunts and shouts and coprolalia
  • Tourniquet - bandage that stops the flow of blood from an artery by applying pressure
  • Toxemia - blood poisoning caused by bacterial toxic substances in the blood; an abnormal condition of pregnancy characterized by hypertension and edema and protein in the urine
  • Toxicity - the degree to which something is poisonous; grave harmfulness or deadliness
  • Toxic shock syndrome - syndrome resulting from a serious acute (sometimes fatal) infection associated with the presence of staphylococcus; characterized by fever and diarrhea and nausea and diffuse erythema and shock; occurs especially in menstruating women using highly absorbent tampons
  • Toxin - a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species
  • Toxoplasmosis - infection caused by parasites transmitted to humans from infected cats; if contracted by a pregnant woman it can result in serious damage to the fetus
  • Trachea - membranous tube with cartilaginous rings that conveys inhaled air from the larynx to the bronchi; one of the tubules forming the respiratory system of most insects and many arachnids
  • Tracheotomy - a surgical operation that creates an opening into the trachea with a tube inserted to provide a passage for air; performed when the pharynx is obstructed by edema or cancer or other causes
  • Trachoma - a chronic contagious viral disease marked by inflammation of the conjunctiva and cornea of the eye and the formation of scar tissue
  • Traction - (orthopedics) the act of pulling on a bone or limb (as in a fracture) to relieve pressure or align parts in a special way during healing; the friction between a body and the surface on which it moves (as between an automobile tire and the road)
  • Transcutaneous - through the unbroken skin; refers to medications applied directly to the skin (creams or ointments) or in time release forms (skin patches)
  • Transferrin - a globulin in blood plasma that carries iron
  • Transient ischemic attack - brief episode in which the brain gets insufficient blood supply; symptoms depend on the site of the blockage
  • Transmissible - (of disease) capable of being transmitted by infection; inherited or inheritable by established rules (usually legal rules) of descent; tending to occur among members of a family usually by heredity
  • Transplant - the act of removing something from one location and introducing it in another location; an operation moving an organ from one organism (the donor) to another (the recipient); (surgery) tissue or organ transplanted from a donor to a recipient; in some cases the patient can be both donor and recipient; verb place the organ of a donor into the body of a recipient; lift and reset in another soil or situation; be transplantable; transfer from one place or period to another
  • Trauma - an emotional wound or shock often having long lasting effects; any physical damage to the body caused by violence or accident or fracture etc.
  • Tremor - an involuntary vibration (as if from illness or fear); a small earthquake; shaking or trembling (usually resulting from weakness or stress or disease); verb shake with seismic vibrations
  • Triage - sorting and allocating aid on the basis of need for or likely benefit from medical treatment or food
  • Trichinosis - infestation by trichina larvae that are transmitted by eating inadequately cooked meat (especially pork); larvae migrate from the intestinal tract to the muscles where they become encysted
  • Tricuspid valve - valve with three cusps; situated between the right atrium and the right ventricle; allows blood to pass from atrium to ventricle and closes to prevent backflow when the ventricle contracts
  • Triglyceride - glyceride occurring naturally in animal and vegetable tissues; it consists of three individual fatty acids bound together in a single large molecule; an important energy source forming much of the fat stored by the body
  • Trimester - one of three divisions of an academic year; a period of three months; especially one of the three three month periods into which human pregnancy is divided
  • Trismus - prolonged spasm of the jaw muscles
  • Trisomy - chrosomal abnormality in which there is one more than the normal number of chromosomes in a cell
  • Trisomy 21 - a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation
  • Tubal ligation - a sterilization procedure with women; both Fallopian tubes are tied in two places and the tubes removed in between the ligations
  • Tuberculin test - a skin test to determine past or present infection with the tuberculosis bacterium; based on hypersensitivity of the skin to tuberculin
  • Tuberculosis - infection transmitted by inhalation or ingestion of tubercle bacilli and manifested in fever and small lesions (usually in the lungs but in various other parts of the body in acute stages)
  • Tumor - an abnormal new mass of tissue that serves no purpose
  • Tunnel vision - visual impairment involving a loss of peripheral vision
  • Turner's syndrome - a chromosomal disorder in females who have only one X chromosome; marked by dwarfism and heart abnormalities and underdeveloped sex organs
  • Tympanoplasty - surgical correction or repair of defects or injuries in the eardrum or the bones of the middle ear
  • Typhoid fever - serious infection marked by intestinal inflammation and ulceration; caused by Salmonella typhosa ingested with food or water
  • Typhus - rickettsial disease transmitted by body lice and characterized by skin rash and high fever
  • Ulcerative colitis - a serious chronic inflammatory disease of the large intestine and rectum characterized by recurrent episodes of abdominal pain and fever and chills and profuse diarrhea
  • Ultraviolet light - radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays
  • Umbilical cord - membranous duct connecting the fetus with the placenta
  • Umbilical hernia - protrusion of the intestine and omentum through a hernia in the abdominal wall near the navel; usually self correcting after birth
  • Unconsciousness - a state lacking normal awareness of the self or environment
  • Urea - the chief solid component of mammalian urine; synthesized from ammonia and carbon dioxide and used as fertilizer and in animal feed and in plastics
  • Uremia - accumulation in the blood of nitrogenous waste products (urea) that are usually excreted in the urine
  • Urethra - duct through which urine is discharged in most mammals and which serves as the male genital duct
  • Urethritis - inflammation of the urethra; results in painful urination
  • Urinalysis - (medicine) the chemical analysis of urine (for medical diagnosis)
  • Urinary tract - the organs and tubes involved in the production and excretion of urine
  • Urticaria - an itchy skin eruption characterized by weals with pale interiors and well defined red margins; usually the result of an allergic response to insect bites or food or drugs
  • Uterus - a hollow muscular organ in the pelvic cavity of females; contains the developing fetus
  • Uvea - the part of the eye that contains the iris and ciliary body and choroid
  • Uveitis - inflammation of the uvea of the eye
  • Vaccine - immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies
  • Vacuum aspiration - a method of induced abortion; prior to the 14th week of gestation the embryo and placenta are removed by applying suction to the dilated cervix
  • Vagina - the lower part of the female reproductive tract; a moist canal in female mammals extending from the labia minora to the uterus
  • Vaginismus - muscular contraction that causes the vagina to close; usually an anxiety reaction before coitus or pelvic examination
  • Vaginitis - inflammation of the vagina (usually associated with candidiasis)
  • Valve - control consisting of a mechanical device for controlling the flow of a fluid; device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone; a structure in a hollow organ (like the heart) with a flap to insure one way flow of fluid through it
  • Valvotomy - incision into a stenosed cardiac valve to relieve the obstruction
  • Valvular heart disease - heart disease caused by stenosis of the cardiac valves and obstructed blood flow or caused by degeneration and blood regurgitation
  • Varicella - an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body
  • Varicocele - dilatation of the veins associated with the spermatic cord in the testes
  • Variola - a highly contagious viral disease characterized by fever and weakness and skin eruption with pustules that form scabs that slough off leaving scars
  • Vascular - of or relating to or having vessels that conduct and circulate fluids
  • Vas deferens - a duct that carries spermatozoa from the epididymis to the ejaculatory duct
  • Vasectomy - surgical procedure that removes all or part of the vas deferens (usually as a means of sterilization); is sometimes reversible
  • Vasodilation - dilation of blood vessels (especially the arteries)
  • VD - a communicable infection transmitted by sexual intercourse or genital contact
  • Vein - one of the horny ribs that stiffen and support the wing of an insect; a blood vessel that carries blood from the capillaries toward the heart; a distinctive style or manner; a layer of ore between layers of rock; any of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other plant organ; verb make a veinlike pattern
  • Venereal disease - a communicable infection transmitted by sexual intercourse or genital contact
  • Venipuncture - (medicine) puncture of a vein through the skin in order to withdraw blood for analysis or to start an intravenous drip or to inject medication or a radiopaque dye
  • Venography - roentgenographic examination of veins
  • Venom - toxin secreted by animals; secreted by certain snakes and poisonous insects (e.g., spiders and scorpions); feeling a need to see others suffer
  • Ventilation - the act of supplying fresh air and getting rid of foul air; a mechanical system in a building that provides fresh air; the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation; free and open discussion of (or debate on) some question of public interest
  • Ventilator - a device (such as a fan) that introduces fresh air or expels foul air; a device that facilitates breathing in cases of respiratory failure
  • Ventricle - a chamber of the heart that receives blood from an atrium and pumps it to the arteries; one of four connected cavities in the brain; is continuous with the central canal of the spinal cord and contains cerebrospinal fluid
  • Ventricular fibrillation - fibrillation of heart muscles resulting in interference with rhythmic contractions of the ventricles and possibly leading to cardiac arrest
  • Ventricular septal defect - a common congenital heart defect; an abnormal opening in the septum dividing the ventricles allows blood to pass directly from the left to the right ventricle; large openings may cause congestive heart failure
  • Vernix - a white cheeselike protective material that covers the skin of a fetus
  • Version - manual turning of a fetus in the uterus (usually to aid delivery); something a little different from others of the same type; an interpretation of a matter from a particular viewpoint; a mental representation of the meaning or significance of something; a written work (as a novel) that has been recast in a new form; a written communication in a second language having the same meaning as the written communication in a first language
  • Vertebra - one of the bony segments of the spinal column
  • Vertigo - a reeling sensation; a feeling that you are about to fall
  • Very low density lipoprotein - large lipoproteins rich in triglycerides; VLDLs circulate through the blood giving up their triglycerides to fat and muscle tissue until the VLDL remnants are modified and converted into LDL
  • Vesicle - a small anatomically normal sac or bladderlike structure (especially one containing fluid)
  • Viral - relating to or caused by a virus
  • Viremia - the presence of a virus in the blood stream
  • Virilization - the abnormal development of male sexual characteristics in a female (usually as the result of hormone therapies or adrenal malfunction)
  • Virulence - extreme hostility; extreme harmfulness (as the capacity of a microorganism to cause disease)
  • Virus - (virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein; a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer; a harmful or corrupting agency
  • Visual acuity - sharpness of vision; the visual ability to resolve fine detail (usually measured by a Snellen chart)
  • Visual field - all of the points of the physical environment that can be perceived by a stable eye at a given moment
  • Vital sign - sign of life; usually an indicator of a person's general physical condition
  • Vitamin A - any of several fat soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
  • Vitamin B complex - originally thought to be a single vitamin but now separated into several B vitamins
  • Vitamin B6 - a B vitamin that is essential for metabolism of amino acids and starch
  • Vitamin B12 - a B vitamin that is used to treat pernicious anemia
  • Vitamin C - a vitamin found in fresh fruits (especially citrus fruits) and vegetables; prevents scurvy
  • Vitamin D - a fat soluble vitamin that prevents rickets
  • Vitamin E - a fat soluble vitamin that is essential for normal reproduction; an important antioxidant that neutralizes free radicals in the body
  • Vitamin K - a fat soluble vitamin that helps in the clotting of blood
  • Vitiligo - an acquired skin disease characterized by patches of unpigmented skin (often surrounded by a heavily pigmented border)
  • Vitreous humor - the clear colorless transparent jelly that fills the posterior chamber of the eyeball
  • VLDL - large lipoproteins rich in triglycerides; VLDLs circulate through the blood giving up their triglycerides to fat and muscle tissue until the VLDL remnants are modified and converted into LDL
  • Volvulus - abnormal twisting of the intestines (usually in the are of the ileum or sigmoid colon) resulting in intestinal obstruction
  • Von Willebrand's disease - a form of hemophilia discovered by Erik von Willebrand; a genetic disorder that is inherited as an autosomal recessive trait; characterized by a deficiency of the coagulation factor and by mucosal bleeding
  • V - the 22nd letter of the Roman alphabet; a unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt; equivalent to the potential difference across a resistance of 1 ohm when 1 ampere of current flows through it; a soft silvery white toxic metallic element used in steel alloys; it occurs in several complex minerals including carnotite and vanadinite
  • Vulva - external parts of the female genitalia
  • Wart - (pathology) a firm abnormal elevated blemish on the skin; caused by a virus; any small rounded protuberance (as on certain plants or animals)
  • Wernicke's encephalopathy - inflammatory degenerative disease of the brain caused by thiamine deficiency that is usually associated with alcoholism
  • Wheeze - breathing with a husky or whistling sound; (Briticism) a clever or amusing scheme or trick; verb breathe with difficulty
  • Whiplash injury - an injury to the neck (the cervical vertebrae) resulting from rapid acceleration or deceleration (as in an automobile accident)
  • White blood cell - blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system
  • Whitehead - a small whitish lump in the skin due to a clogged sebaceous gland; English philosopher and mathematician who collaborated with Bertrand Russell (1861 1947)
  • Whitlow - a purulent infection at the end of a finger or toe in the area surrounding the nail
  • Wilson's disease - a rare inherited disorder of copper metabolism; copper accumulates in the liver and then in the red blood cells and brain
  • Xanthine - crystalline oxidation product of the metabolism of nucleoproteins; precursor of uric acid; found in many organs and in urine
  • Xanthomatosis - widespread xanthomas (especially on elbows and knees); often associated with a disorder of lipid metabolism
  • X chromosome - the sex chromosome that is present in both sexes: singly in males and doubly in females
  • Xeroderma pigmentosum - a rare genetic condition characterized by an eruption of exposed skin occurring in childhood and photosensitivity with severe sunburn; inherited as a recessive autosomal trait in which DNA repair processes are defective so they are more likely to chromosome breaks and cancers when exposed to ultraviolet light
  • Xerophthalmia - abnormal dryness of the conjunctiva and cornea of the eyes; may be due to a systemic deficiency of vitamin A
  • X ray - a radiogram made by exposing photographic film to X rays; used in medical diagnosis; electromagnetic radiation of short wavelength produced when high speed electrons strike a solid target; verb take an x ray of something or somebody; examine by taking x rays
  • Yellow fever - caused by a flavivirus transmitted by a mosquito
  • Zoonosis - an animal disease that can be transmitted to humans
  • Zygote - the cell resulting from the union of an ovum and a spermatozoon (including the organism that develops from that cell)
  • Zygote intrafallopian transfer is a method used to treat infertility in which an egg fertilized outside the body is placed into a woman's fallopian tube

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