Why are the veins under the skin blue in colour?

Answer 1

Because our blood is actually the color blue, when exposed to air it oxidizes (or enriches the blood cells with oxygen) and changes color to red.

Answer 2

First thing: Blood is *never* blue. This is a myth. 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.
http://www.globalclassroom.org/blublud.html
http://www.seps.org/oracle/oracle.archive/Life_Science.Health/2000.10/000972421581.26676

Blood is a bright red in its oxygenated form (i.e., leaving the lungs), when hemoglobin is bound to oxygen to form oxyhemoglobin. It's a dark red in its deoxygenated form (i.e., returning to the lungs), when hemoglobin is bound to carbon dioxide to form carboxyhemoglobin.


Veins appear blue because light, penetrating the skin, is absorbed and reflected back to the eye. Since only the higher energy wavelengths can do this (lower energy wavelengths just don't have the *oomph*), only higher energy wavelengths are seen. And higher energy wavelengths are what we call "blue."


In an experiment, glass tubes were filled with blood and immersed in milk, milk having a similar ratio of fat, proteins, and water in emulsion as skin. At a certain depth, the tubes appeared blue.


As a phlebotomist (a person who draws blood) at the local university hospital, I drew hundreds of samples of venous blood. Almost all samples were dark red. Those that weren't were usually because people were on enriched oxygen systems.


At the same time, respiratory therapists drew blood from an artery, not a vein. These samples were characteristically bright red, unless the patient was having difficulty breathing (asthma, people with one lung, pneumonia, emphysema, whatever).

So, your veins may look blue, but even a blueblood will bleed red.

Answer 3

that's because of the fact the deep pink colour of the blood plus the colour of the blood vessel and the colour of your fat and pores and skin tissue all mixed mutually, forming the spectacular bluish purplish colour. Arteries look purely approximately a similar way. Even the blood vessels in umbilical cords look a similar. BTW, there's a sprint bit colour distinction interior the blood in veins vs. arteries. Arterial blood is plenty deeper pink because of the fact it is oxygenated.

Answer 4

Everyone who said that our blood is actually blue is completely wrong! Your veins are blue for the same reason the sky is blue. Which is the way in which the light is reflected onto it. I could go into much more detail but i don't remember half the names of the words I was taught about it.

Answer 5

they arent veins, they are arteries.
The blood has travelled through the lungs and contains oxygen so it appears blue, the blood travels back to the heart in veins and is de-oxygenated and it red

Answer 6

because your blood is blue! See how when you pinch your arm and the skin goes white but the veins are blue? blue blood.

Answer 7

Why should they be any other color? You got something against blue? Sometimes blue tastes like green, though.

Answer 8

Thank goodness Melli gave a sensible answer. I was beginning to think that everyone on here was stupid.

Answer 9

they carry the used blood back to your heart.

Answer 10

because your blood is blue until it gets oxygen then turns red.