What color is blood?

[Raizinman]

We all see RED when we cut our selves, but is blood really red? I’ve heard that it is actually BLUE, but when it comes into contact with oxygen in the air, it turn back to red. Why do the veins in your arm look blue? How come when blood is drawn out of your body with an airtight syringe it is red? Shouldn’t it be blue? When you hold your hand, ear or foot in front of a very bright light, the inside appears red, not blue. Where is this blue blood I keep hearing about?

 

[jlee]

http://www.biology-online.org/biology-forum/about763.html

 

[Bignate603]

It's bright red when its heavily oxygenated and deep red when it's not. The whole red/blue thing is exaggerated in anatomy drawings to help people identify the arteries and veins.

They have some good pictures in the wikipedia article on blood that shows the difference. Color of blood

 

[amdhunter]

 

[IronWing]

OP, were you reading the Fugate story?

 

[BladeVenom]

Crustaceans have blue blood. They use hemocyanin instead of hemoglobin.

 

[Pardus]

http://wiki.answers.com/Q/What_color_is_blood

What color is blood?


Answer
In humans and other hemoglobin-using creatures, oxygenated blood is bright red. This is due to oxygenated iron in the red blood cells. Deoxygenated blood is a darker shade of red, which can be seen during blood donation and when venous blood samples are taken. However, due to an optical effect caused by the way in which light penetrates through the skin, veins typically appear blue in color. This has led to a common misconception that venous blood is blue before it is exposed to air. Another reason for this misconception is that medical charts always show venous blood as blue in order to distinguish it from arterial blood which is depicted as red on the same chart.

The blood of horseshoe crabs is blue, which is a result of its high content in copper-based hemocyanin instead of the iron-based hemoglobin found, for example, in humans.

 

[Pheran]

We all see RED when we cut our selves, but is blood really red? I’ve heard that it is actually BLUE, but when it comes into contact with oxygen in the air, it turn back to red. Why do the veins in your arm look blue? How come when blood is drawn out of your body with an airtight syringe it is red? Shouldn’t it be blue? When you hold your hand, ear or foot in front of a very bright light, the inside appears red, not blue. Where is this blue blood I keep hearing about?

If you were paying any attention here, you would have learned something.