Question

Почему вены синие, а кровь красная?

Answer 1

Артериальная кровь насыщена кислородом, и цвет у нее алый. Венозная тоже содержит кислород, но не такой концентрации. Она багровая. Красный цвет -  цвет от гемоглобина, в состав которого входит железо. Восстановленный гемоглобин имеет яркий цвет. А окисленный - темнеет. В книгах по анатомии, показано, что вены синие. Если же посмотреть на вену, наполненную кровью, то она синеватого цвета. У вены стенки тонкие, а кровь темная. Из-за этого и синеватый оттенок. 

Answer 2

Why are veins blue and blood red?

Veins appear blue because of the way light interacts with the skin and the blood vessels beneath it. The color of blood itself is actually red, but it can appear different depending on the circumstances. Here's a breakdown of why veins appear blue and blood appears red:

Veins appear blue: - Veins carry deoxygenated blood back to the heart. This blood is darker in color because it has less oxygen. - When light passes through the skin, it gets absorbed by the surrounding tissues. The longer wavelengths of light, such as red and orange, are absorbed more than the shorter wavelengths, such as blue and green. - The blue light that is not absorbed by the tissues is scattered and reflected back to our eyes, making the veins appear blue.

Blood appears red: - Blood is red because of the iron contained in red blood cells. This iron binds to oxygen, giving blood its red color. - When blood is oxygenated, such as in arteries, it appears bright red. Oxygen-rich blood is typically seen in arteries that are closer to the surface of the skin. - When blood is deoxygenated, such as in veins, it appears darker red or even bluish. Deoxygenated blood is typically seen in veins that are deeper beneath the skin.

In summary, veins appear blue due to the way light interacts with the skin and the blood vessels beneath it. Blood itself is red, but its color can vary depending on the oxygenation level.

I hope this explanation helps! Let me know if you have any further questions.