2007-12-30 15:06:57 · 9 answers · asked by SANN 1 in Science & Mathematics ➔ Biology
Because of the presence of a protein called hemoglobin. Why is hemoglobin red? Because it has iron in it. How does iron make hemoglobin red? I don't know yet, but it is already a question of quantum chemistry, so its definitely off-tangent.
Blood, in all of a person's blood vessels, is red. (Just don't throw the philosophical question that why should it have any color while no one's watching it or that since no light shines on it.) Blood in the arteries, though, is a brighter red because of the presence of oxygen that binds into the iron ions (activating its electrons to a certain energy, thus producing the color) of the hemoglobin. Blood in the veins, on the other hand, has fewer if it has any oxygen molecules, so the iron has no oxygen molecules to activate it, and the color is a duller red.
2007-12-30 15:13:35 · answer #1 · answered by pecier 3 · 1⤊ 0⤋
The blood in the arteries is red because it contains Red Blood Cells also known as erythrocytes and they contain hemoglobin inside them which has an iron molecule in it wich carries oxygen, therefore the red blood cells are oxygen enriched. If they had no oxyguen then they are blood vesseils in the veins bringing the blood back to the heart so then it can undergo the cycle again and get oxygen aain and be carried into the artery from the veins and supply oxygen to the body
2007-12-30 15:34:59 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Arteries (except for the pulmonary arteries) carry oxygenated blood. Blood carrying oxygen appears brighter red.
2007-12-30 15:14:38 · answer #3 · answered by ecolink 7 · 0⤊ 0⤋
Blood in arteries have been oxygenated by the lungs so is bright red. Venous blood is without oxygen so is a dark red.
2007-12-30 15:10:51 · answer #4 · answered by Emerson 5 · 1⤊ 0⤋
arteries are carrying blood away from the heart, they have been oxygenated by the lungs and flow faster than blood in veins. Veins bring blood back to the heart (this blood doesn't have much oxygen left in it)
def:brighter=more oxygen
2007-12-30 15:25:03 · answer #5 · answered by curious 1 · 0⤊ 0⤋
The red blood cells are carrying oxygen giving them a brighter red color than blood returning to the heart.
2007-12-30 15:11:05 · answer #6 · answered by Anonymous · 0⤊ 0⤋
When blood is in the artery, it has just been oxygenated via the lungs, so the red blood cells (RBC) appear bright red, due to the hemoglobin.
Dying or deoxygenated RBC appear darker red in color.
2007-12-30 15:10:24 · answer #7 · answered by ¿ /\/ 馬 ? 7 · 2⤊ 0⤋
No
2017-02-12 21:56:06 · answer #8 · answered by Anonymous · 0⤊ 0⤋
because there is oxygen in it ...
2007-12-30 15:16:37 · answer #9 · answered by Pat 1 · 0⤊ 0⤋