Digestion

From WikiMD
Jump to navigation Jump to search

Digestion and absorption occur in the digestive tract. After the nutrients are absorbed, they are available to all cells in the body and are utilized by the body cells in metabolism.

The digestive system prepares nutrients for utilization by body cells through six activities, or functions.

Ingestion

The first activity of the digestive system is to take in food through the mouth. This process, called ingestion, has to take place before anything else can happen.

Mechanical Digestion

The large pieces of food that are ingested have to be broken into smaller particles that can be acted upon by various enzymes. This is mechanical digestion, which begins in the mouth with chewing or mastication and continues with churning and mixing actions in the stomach.

Chemical Digestion

The complex molecules of carbohydrates, proteins, and fats are transformed by chemical digestion into smaller molecules that can be absorbed and utilized by the cells. Chemical digestion, through a process called hydrolysis, uses water and digestive enzymes to break down the complex molecules. Digestive enzymes speed up the hydrolysis process, which is otherwise very slow.

Movements

After ingestion and mastication, the food particles move from the mouth into the pharynx, then into the esophagus. This movement is deglutition, or swallowing. Mixing movements occur in the stomach as a result of smooth muscle contraction. These repetitive contractions usually occur in small segments of the digestive tract and mix the food particles with enzymes and other fluids. The movements that propel the food particles through the digestive tract are called peristalsis. These are rhythmic waves of contractions that move the food particles through the various regions in which mechanical and chemical digestion takes place.

Absorption

The simple molecules that result from chemical digestion pass through cell membranes of the lining in the small intestine into the blood or lymph capillaries. This process is called absorption.

Elimination

The food molecules that cannot be digested or absorbed need to be eliminated from the body. The removal of indigestible wastes through the anus, in the form of feces, is defecation or elimination.


Apple bitten.svg
WikiMD is a free medical encyclopedia and wellnesspedia moderated by medical professionals.


Topics related to Digestion

See other topics, articles and terms related to Digestion on WikiMD.

Frequently Asked Questions

Faq-icon.png

External articles

Wikipedia


Recent Articles

Most recent articles for Digestion:

Most Cited:

Review Articles:

Magazine Articles:

In the NEWS:

Media & Blogs

Media articles for Digestion:

Books and news:

BLOGS:


Health Topics: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Wellness

Scientific Articles

Evidence based medicine for Digestion:

Clinical trials for Digestion:

Resources & Links

Patient resources for Digestion:

Sponsored links - W8MD weight loss, sleep & medspa centers

Social media - Digestion
Reddit
Quora.png
Pins
Instagram
YouTube videos
Bing.png

Help WikiMD

Find something you can improve? Join WikiMD as an an editor and help improve this page or others.

Apple bitten.svg

WikiMD is a free medical encyclopedia and wellnesspedia moderated by medical professionals.



Health topics | USMLE
A-Z health topics | Popular health topics | Drugs | Alternative medicines | Medicine portal
Medical books.jpg

A |  B |  C |  D |  E |  F |  G |  H |  I |  J |  K |  L |  M | N |  O |  P |  Q |  R |  S |  T |  U |  V |  W |  X |  Y |  Z

Index of health articles | Medicines | Dentistry portal | Medications portal | Pharmacology portal | Psychiatry portal

Glossaries and dictionaries | Comprehensive dictionary of medicine | Encyclopedia of medicine

Medicine | Health topics | Anatomy | Diet | Pediatrics | Cardiology | Neurology | Pathology | Psychiatry | Obesity | Pharmacology | Rheumatology | Gynecology

W8MD logo

Ad. Tired of being overweight?. W8MD's insurance weight loss can HELP*

Lose weight King of Prussia, PA | Lose weight NYC | Lose weight NJ | Lose weight Philadelphia | Advertise

Quick links: Medicine Portal | Encyclopedia‏‎‏‎ | Gray's Anatomy‏‎ | Topics‏‎ |‏‎ Diseases‏‎ | Drugs | Wellness | Obesity‏‎ | Metabolic syndrome | Weight loss*
Disclaimer: The entire contents of WIKIMD.ORG are for informational purposes only and do not render medical advice or professional services. If you have a medical emergency, you should CALL 911 immediately! Given the nature of the wiki, the information provided may not be accurate, misleading and or incorrect. Use the information on this wiki at your own risk! See full Disclaimer.
Link to this page: <a href="http://www.wikimd.org/wiki/Digestion">Digestion</a>

  • Individual results may vary for weight loss from our sponsors.

Our sponsors WikiMD is supported by W8MD weight loss, sleep and medical aesthetic centers.