Is your blood blue before it comes gushing out? If not then why are your veins blue?
Yes, it’s blue. Oxygen in the blood makes it red; the blue stuff is on its way back to the lungs to pick up more. On contact with air, it sucks up the oxygen so fast you can’t see the blue part.
Researchers withdrew some blood from Frank Shorter while he was running on a treadmill; it was black, there was so little oxygen left in it.
then why is it red when they withdraw a tube full for a blood test?
Blood in the arteries is bright red. Blood in the veins is dark red. Veins look blue because the skin absorbs most of the red light. Mailbag item: If blood is red why do your veins look blue?
also why cant you look at your skin and tell the difference between veins and arteries? wouldnt the veins be blue and the arteries red?
Here’s a column. It’s different shades of red.
Darn simulpost. But then again, it answers your third question too.
If it’s red, then they’re drawing it from an artery, not a vein. Arteries carry oxygenated blood from the lungs, (with one expection) and veins carry deoxygenated blood to the lungs (with one exception.)
Arteries are more important than veins in terms of what your body needs - oxygenated blood. For this reason, they are more protected, lying deep within the body, usually near bones. It is tough to withdraw blood from an artery with a needle and syringe.
Veins return blood. They lie near the surface. This is where most blood is drawn. If you have blood drawn from the inside of your elbow or back of hand, it is from a vein.
Blood in arteries is bright red from the oxygenation.
Blood in veins is dark red from lack of oxygenation.
Also, the walls of arteries tend to be thicker and more opaque than those of veins, which makes them harder to see under the skin.