Veins

From WikiMD
Jump to navigation Jump to search

Veins

Veins carry blood toward the heart. After blood passes through the capillaries, it enters the smallest veins, called venules. From the venules, it flows into progressively larger and larger veins until it reaches the heart. In the pulmonary circuit, the pulmonary veins transport blood from the lungs to the left atrium of the heart. This blood has a high oxygen content because it has just been oxygenated in the lungs. Systemic veins transport blood from the body tissue to the right atrium of the heart. This blood has a reduced oxygen content because the oxygen has been used for metabolic activities in the tissue cells.

illustration of the walls of a vein

The walls of veins have the same three layers as the arteries. Although all the layers are present, there is less smooth muscle and connective tissue. This makes the walls of veins thinner than those of arteries, which is related to the fact that blood in the veins has less pressure than in the arteries. Because the walls of the veins are thinner and less rigid than arteries, veins can hold more blood. Almost 70 percent of the total blood volume is in the veins at any given time. Medium and large veins have venous valves, similar to the semilunar valves associated with the heart, that help keep the blood flowing toward the heart. Venous valves are especially important in the arms and legs, where they prevent the backflow of blood in response to the pull of gravity.



Topics related to Veins

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

Frequently Asked Questions

Faq-icon.png

External articles

Wikipedia


Recent Articles

Most recent articles for Veins:

Most Cited:

Review Articles:

Magazine Articles:

In the NEWS:

Media & Blogs

Media articles for Veins:

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 Veins:

Clinical trials for Veins:

Resources & Links

Patient resources for Veins:

Sponsored links - W8MD weight loss, sleep & medspa centers

Social media - Veins
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

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/Veins">Veins</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.