Why Do Veins Appear Blue? | Uncovering the Mystery

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In summary, sulfhemoglobinemia is a condition in which the blood is blue due to an abnormal amount of sulfhemoglobin.
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The blood that oozes out when a vein is cut is red...then y do veins appear bluish to our eyes? Some say its because its deoxygenated...but if so then d blood oozing out should have also been blue..but it isn't...so what's d reason?
 
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Veins appear blue because the subcutaneous fat absorbs low-frequency light, permitting only the highly energetic blue wavelengths to penetrate through to the dark vein and reflect back to the viewer. A study found the color of blood vessels is determined by the following factors: the scattering and absorption characteristics of skin at different wavelengths, the oxygenation state of blood, which affects its absorption properties, the diameter and the depth of the vessels, and the visual perception process. When a vein is drained of blood and removed from an organism it appears grey-white. (Kienle, Alwin; Lilge, Lothar; Vitkin, I. Alex; Patterson, Michael S.; Wilson, Brian C.; Hibst, Raimund; Steiner, Rudolf (1 March 1996). "Why do veins appear blue? A new look at an old question". Applied Optics 35 (7): 1151.) (https://en.wikipedia.org/wiki/Vein#Color)
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IAmUnique said:
but if so then d blood oozing out should have also been blue..but it isn't..
I didn't see you mention, 'Human' anywhere, so ... i could say.. the blood is blue, in case of octopus, shrimps,etc. :)
 
  • #5
Except in very cases when it's green.

Presentation[edit]
Symptoms include a blueish or greenish discoloration of the blood, skin, and mucous membranes, even though a blood count test may not show any abnormalities in the blood. This discoloration is called cyanosis, and is caused by greater than 5 grams per cent of deoxyhemaglobinemia, or 1.5 grams per cent of methemaglobinemia, or 0.5 grams per cent of sulphemaglobinemia, all serious medical abnormalities.

Notable cases[edit]
On June 8, 2007, Canadian anesthesiologists Dr. Stephan Schwarz, Dr. Giuseppe Del Vicario, and Dr. Alana Flexman presented an unusual case in The Lancet.[2] A 42-year-old male patient was brought into Vancouver's St. Paul's Hospitalafter falling asleep in a kneeling position, which caused compartment syndrome and a buildup of pressure in his legs. When doctors drew the man's blood prior to performing the surgery to relieve the pressure from the man's legs, they noted his blood was green. A sample of the blood was immediately sent to a lab. In this case, sulfhemoglobinaemia was possibly caused by the patient taking higher-than-prescribed doses of sumatriptan.[3][4][5]

It is also believed William Thomson, 1st Baron Kelvin suffered from sulfhemoglobinemia.

http://en.wikipedia.org/wiki/Sulfhemoglobinemia
 
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1. Why do veins appear blue?

The color of veins is not actually blue, but it may appear blue due to the way light interacts with our skin. Veins appear blue because blue light is able to penetrate through the skin and reflect off the blood vessels, making them appear blue.

2. Are all veins blue?

No, not all veins appear blue. The color of veins may vary depending on the location in the body and the thickness of the skin. Some veins closer to the surface may appear more blue, while deeper veins may appear more purple or even green.

3. Do veins only carry deoxygenated blood?

Contrary to popular belief, veins carry both oxygenated and deoxygenated blood. However, veins do carry a higher percentage of deoxygenated blood compared to arteries.

4. Why are veins closer to the surface of the skin?

Veins are closer to the surface of the skin because they have a lower pressure compared to arteries. This lower pressure allows them to be located closer to the surface of the skin, making it easier for them to return blood back to the heart.

5. Do veins have any other functions besides carrying blood?

Yes, veins also play a role in regulating body temperature and helping with the immune response. They also act as a reservoir for blood, storing excess blood that can be released when our body needs it, such as during physical activity.

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