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Why Are Veins Blue If Blood Is Red?

Body Knowledge: Red Blood, Blue Veins?

There is a common misconception among kids that blood, as it courses through our veins on its return trip back to the heart, is blue.

When you look at your arms you see blue veins, but this is a trick of light, or rather a problem with wavelengths. According to Live Science, the blue waves of light are not absorbed by your skin, unlike red light waves, so blue is the color you see because it bounces back.

So what does happen to your blood as it moves about your body? Learn the details by reading more.

Blood is pumped into your lungs by the heart to be replenished with oxygen, and then the bright red blood is pumped to all parts of your body through arteries and eventually into tiny capillaries. It is here that the blood provides oxygen to your body's tissue. Rather than turning blue, the oxygen-depleted blood hits your veins in a dark red hue. Another capillary fact to chew on: your lips are red because they are full of capillaries.

Join The Conversation
C-Ruth C-Ruth 6 years
Who knew this post would elicit so much controversy.
Spectra Spectra 7 years
Who thinks that blood in the veins is actually blue?? My veins look kind of greenish-blue...depending on your skin tone, your veins don't always look blue in the light. It's pretty cool how different blood looks once it's been oxygenated. It really gets a lot brighter red, really quickly.
fatsoleus fatsoleus 7 years
About the "common misconception," it's actually something that I was taught in a highschool biology class, of all places. My teacher explained that the iron present in red blood cells is oxidized, or "rusted," when the blood is oxygen-rich. Veins carrying oxygen-poor blood back to the heart, she reasoned, was bluish, although if you were to cut open a vein the blood you saw would be red, since it would reuptake oxygen as soon as it came in contact with the air... Needless to say, with pseudo-scientific explanations like these, I couldn't really bring myself to respect my teacher much. Also, Fit, as Ms.Choo pointed out above, you should change the description you wrote, since it's precisely blue light that doesn't get absorbed!
bethinabox bethinabox 7 years
How funny would it be if your blood actually WAS blue? :P Yogaforlife, I completely feel your pain. My legs are crazy pale and there are just so many blue veins! It's ridiculous!
MsChoo MsChoo 7 years
You mean red waves. When an objects absorbs light, you see the colour that wasnt absorbed. So if you see a green apple that means every other colour except green is being absorbed, and green is reflected so you see green. And plus red has a higher frequency that blue does making it easier to penetrate skin (think gamma waves and how they can kill you cause their frequency is really really high)
kimmieb124 kimmieb124 7 years
Anon...I was wondering the same thing!
Yogaforlife Yogaforlife 7 years
I have to say, I wish my blue veins weren't so apparent. In about another month, I'll be so pale as to be practically translucent and I look like a road map with all those veins showing everywhere.
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