2007-09-10 14:41:44 · 8 answers · asked by claidifl 4 in Science & Mathematics ➔ Biology
The blue colour is due to the lack of fresh oxygen in the blood.
Arteries carry oxygenated blood to all parts of the body, veins then return the blood that has had the oxygen absorbed by the cells back to the heart and lungs to pick up more oxygen (like a conveyor belt).
When blood has less oxygen, it takes on a bluish colour.
2007-09-10 14:47:19 · answer #1 · answered by Anonymous · 4⤊ 0⤋
No, despite the common myth, deoxygenated blood is NOT blue. It is a much darker red than you normally see. When you get a cut, the blood runs very bright red, but if you have blood drawn from your arm (the tube the blood is drawn into is a vacuum, so there is no oxygen), it's a very dark red.
The blue color is the veins (and arteries) themselves, seen through the tissue of your arm. Light can only penetrate so far down through the skin, and blue light can penetrate the easiest, therefore deeper veins and arteries tend to show up blue.
A dead (or very cold) person appears blue because the blood no longer actively pumps through their system. When you get cold, the capillaries constrict, shunting blood away from the skin to conserve warmth. You see this if you swim in really cold water. After a while, your lips turn bluish. When a person dies, gravity takes over, and blood pools to the bottom, depending on which way they are lying (a dead person's upward-facing side would be blue, but if you turned them over, the underside would be a dark purple). Either way, with blood diverted from the skin, the natural color of the tissues shows through as a grayish blue.
2007-09-11 09:34:01 · answer #2 · answered by andymanec 7 · 1⤊ 0⤋
Human blood is red, ranging from bright red when oxygenated to dark red when not. It owes its colour to hemoglobin, a protein compound containing iron, to which oxygen binds. Blood is never blue, but veins appear blue because light is diffused by skin. The blood inside is dark red and exhibits poor light reflection. From a physiological perspective, veins and arteries appear similar when skin is removed and are seen directly. There exists a popular misconception that deoxygenated blood is blue and that blood only becomes red when it comes into contact with oxygen. I hope this should be sufficient to answer your second question too.
2016-04-04 01:16:00 · answer #3 · answered by Anonymous · 0⤊ 0⤋
As several other people have said, deoxygenated blood is indeed blue. Why is it always red whenever you get a nick? Because, even if you open a vein, the deoxygenated blood immediately picks up oxygen from the atmosphere and becomes red.
It explains why drowning victims are bluish in color; they died because their bodies used up all the oxygen stored in their blood and they weren't able to get more.
2007-09-10 15:00:37 · answer #4 · answered by Lucas C 7 · 1⤊ 2⤋
Deoxygenated blood is still dark blue, regardless of what color the blood vessels are. The carbon dioxide and other wastes that the cells turn the cells this color. Oxygentated blood essentially is Oxygen attracted to the Iron atom in the center of hemoglobin. Essentially, rust is what makes your blood cells red.
2007-09-10 14:51:49 · answer #5 · answered by fmed64 3 · 2⤊ 2⤋
Veins are returning UNoxygentated blood, which appears a bluish color. Arteries carry oxygen rich blood, which appears more red.
2007-09-10 14:46:51 · answer #6 · answered by ab_n_me2 2 · 4⤊ 1⤋
b/c b4 the blood goes through our hearts its blue so thats y our vein look blue
2007-09-10 14:49:35 · answer #7 · answered by Anonymous · 0⤊ 6⤋
the yellowness of our skin ? thats what ive thought it was
2007-09-10 14:46:04 · answer #8 · answered by some guy 5 · 0⤊ 6⤋