Venous blood
Venous blood is deoxygenated
Venous blood is typically colder than arterial blood,[1] and has a lower oxygen content and pH. It also has lower concentrations of glucose and other nutrients and has higher concentrations of urea and other waste products. The difference in the oxygen content of arterial blood and venous blood is known as the arteriovenous oxygen difference.[citation needed]
Most medical laboratory tests are conducted on venous blood, with the exception of
Color
The color of human blood ranges from bright red when oxygenated to a darker red when deoxygenated.[2] It owes its color to hemoglobin, to which oxygen binds. Deoxygenated blood is darker due to the difference in shape of the red blood cell when oxygen binds to haemoglobin in the blood cell (oxygenated) versus does not bind to it (deoxygenated). Though veins might make it appear as such, human blood is never naturally blue. [3]
The blue appearance of surface veins is caused mostly by the scattering of blue light away from the outside of venous tissue if the vein is at 0.5 mm deep or more. Veins and arteries appear similar when skin is removed and are seen directly.[4][5]
References
- ^ Bostock, J. (1826). An elementary system of physiology. Vol. 1. p. 263. Retrieved 2013-03-16.
- ^ "Is blood really blue". scienceworld.ca/blog/blood-really-blue. 10 December 2015. Retrieved 2019-07-31.
- ^ "UCSB Science Line". scienceline.ucsb.edu. Retrieved 2022-03-07.
- ISBN 978-0-335-23588-9. Retrieved 7 May 2013.
- PMID 21085227. Retrieved 7 May 2013.