Venous blood

WikiDoc Resources for Venous blood
Articles
Most recent articles on Venous blood Most cited articles on Venous blood Review articles on Venous blood Articles on Venous blood in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Venous blood Images of Venous blood Photos of Venous blood Podcasts & MP3s on Venous blood Videos on Venous blood
Evidence Based Medicine
Cochrane Collaboration on Venous blood Bandolier on Venous blood TRIP on Venous blood
Clinical Trials
Ongoing Trials on Venous blood at Clinical Trials.gov Trial results on Venous blood Clinical Trials on Venous blood at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Venous blood NICE Guidance on Venous blood NHS PRODIGY Guidance FDA on Venous blood CDC on Venous blood
Books
Books on Venous blood
News
Venous blood in the news Be alerted to news on Venous blood News trends on Venous blood
Commentary
Blogs on Venous blood
Definitions
Definitions of Venous blood
Patient Resources / Community
Patient resources on Venous blood Discussion groups on Venous blood Patient Handouts on Venous blood Directions to Hospitals Treating Venous blood Risk calculators and risk factors for Venous blood
Healthcare Provider Resources
Symptoms of Venous blood Causes & Risk Factors for Venous blood Diagnostic studies for Venous blood Treatment of Venous blood
Continuing Medical Education (CME)
CME Programs on Venous blood
International
Venous blood en Espanol Venous blood en Francais
Business
Venous blood in the Marketplace Patents on Venous blood
Experimental / Informatics
List of terms related to Venous blood

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In the circulatory system, venous blood is blood returning to the heart. With one exception (the pulmonary vein) this blood is deoxygenated and high in carbon dioxide, having released oxygen and absorbed CO₂ in the tissues. It is also typically warmer than arterial blood, has a lower pH, has lower concentrations of glucose and other nutrients, and has higher concentrations of urea and other waste products.

Venous blood can be obtained by venipuncture (also called phlebotomy), or in small quantities by fingerprick. Most medical laboratory tests are conducted on venous blood, with the exception of arterial blood gases.

Venous blood is often depicted as blue in color in medical diagrams, and veins sometimes look blue when seen through the skin. However, venous blood is actually a dark red color (but looks purple through the opaque skin), while arterial blood is bright red. The appearance of veins as dark blue is a wavelength phenomenon of light, having to do with the reflection of blue light away from the outside of venous tissue if the vein is @ 0.02in deep or more. This is due to the difference in color between deoxyhemoglobin and oxyhemoglobin; the red color ultimately originates from the iron atom in heme. If blood is drawn for a medical test, the dark red color can be seen; however, if it is exposed to oxygen in the air, it will turn bright red like arterial blood.

Template:WikiDoc Sources