why when you look at your viens why are they blue but blood is red???

Question

i have always wondered this can anybody tell me why???

Answer 1

Why do veins look blue? Why do blood vessels in your wrist look blue when they are full of red blood. Yes, the subject of countless speculation and argument. No, it's not because blood is blue until it is oxygenated when it hits the air and suddenly turns blue like my stupid brother tried to argue. All the respondents in here also seem to indicate that erroneous fallacy.


The answer is really quite complicated. There is less red light reflected from the shallow area between the surface and the vessel than blue light because blue light is scattered more. The surrounding tissue reflects back more red.


This does not make the vessel blue, however. It only makes it look blue. The authors had to use Land's retinex model of color vision to show that the contrast between the two areas of the skin are interpreted by the brain in such a way as to make it look blue.


This is the simplest interpretation of a pretty complicated question.

Now if this really a retinex effect you should be able to do a pretty easy experiment. If you eliminate the surrounding color the blue effect should go away. I just took a piece of white paper and punched a round hole in it with a three-hole-punch. When placed over a vein, sure enough I don't see blue. Try it yourself.

In addition, remember, the eye is more receptive to vision the color blue which has the longest or broadest bandwidth among all other colors. It is for this reason that the sky is envisoned as blue.


Another simple scientific medical explanation is that veins carry oxygen- poor or unoxygenated blood while arteries carry oxygenated blood ( obtained from the lungs). Blood is *never* blue. Blood is described as dark red (venous) or bright red (arterial). Our veins look blue because we are looking at them *through* our skin. The blood inside them is dark red and it doesn't reflect light very well. The blood you see when you get hurt is usually venous blood. Arterial blood comes out in spurts. It spurts every time the heart beats. I hope you never see that. Your *blood* does not ever *look* blue. The blue things you see under your skin are veins. Veins are really whitish in color but because the blood is dark and the skin difuses the light, the veins *look* blue.

Answer 2

Your veins are blue, and when blood gets oxygen it turns red. It is also assumed that your blood is blue and changes to a dark red before it gets oxygenated, and turns a bright red when it hits the air.

Answer 3

Blood caries oxygen throughout your body. The red stuff has oxygen (the reason you have blue and red veins). When those veins get to where they go and release the oxygen they turn blue. When blood is out of the body it hits oxygen immediately and turns red. When people die and their lungs can no longer give blood oxygen, they turn sorta blue.

Answer 4

deoxygenated blood has a blue tint to it. This is from the red blood cells who now have a free oxygen receptor and are heading back to your lungs to pick up another one. You don't really see the red bood vessels since they blend in with your skin.

when you bleed, the red blood cells bind oxygen that is in the air which gives the blood a red color even if you nicked a vessel containing blood returning to the lungs.

Answer 5

When oxygen hits blood, it changes from blue to red.

Answer 6

it is because when blood is in your body it is blue but that is before it is mixed with oxygen. as soon as you start to bleed the blood hits the oxygen and it turns red. a chemical reaction

Answer 7

Blood in your veins is BLUE... when oxygen hits blood it turns red.

Answer 8

Ur blood is blue until it hit the air then it truns red.

Answer 9

Blood is only red when it is oxygenated, it is blue when it is not oxygenated, in the veins.

Answer 10

blood is blue until it hits the air and then some chemical reaction turns it red. i heard that somewhere.