how come when u cut yourself the blood is red but inside your veins it is blue?

Question

broxolm its my sons home work not that serious

Answer 1

Deoxygenated blood (ie: blood that does not contain oxygen) is "bluish red*," so to speak, and oxygenated blood, is a true red. The blood that travels in your veins lacks oxygen because it is returning from the tissues (where oxygen was extracted from it). Blood traveling through your arteries is a richer shade of red, since arteries are delivering oxygenated blood from the lungs (where the blood is mixed with oxygen) and out to the tissues.

*What I mean by "blue-ish red" is that the blood is not visibly blue to our eyes- but rather, with respect to the visible light spectrum, the blood shifts more towards the blue end. On a spectrophotometer (an instrument that is used in laboratories to measure light emission), deoxygenated blood is measurably more blue than oxygenated blood- but we can't discern this difference with our eyes. So, essentially, everyone who responded is correct: Deoxygenated blood is blue (as in 'bluer' than oxygenated blood) but it still looks red. This is why, when blood is drawn, it still looks red.

Also, the reason why so many might erroneously think deoxygenated blood is blue is that in anatomy texts, deoxygenated blood is portrayed as blue to differentiate it from oxygenated blood which is always drawn red. Further, through the skin, veins appear to have 'blue-ish' blood in them because the color of the skin combined with the endothelium of veins cause it to appear more blue than it actually is.

Answer 2

All blood is red. Oxygenated blood is bright red, and de-oxygenated blood is dark red.

It looks blue in your veins because the tissue between the blood and the outside world bends the light and makes it look blue. (Like the atmosphere makes the sky look blue)

The proof that the blood in your veins is NOT blue is this: if you have blood drawn into a syringe from a vein (or give blood at the red cross) it does not come into contact with air. It is still red.

Answer 3

Veins carry deoxygenated blood, which happens to be blue cause the red pigment of hemoglobin comes out when there is a presence of oxygen. Arteries carry oxygenated blood which is red. But, cutting an artery is very dangerous and hard to do. So we cut veins, which carry blood that doesn't have oxygen, and when the blood comes into contact with the atmosphere, it is getting oxygen, so it turns red cuz it activates the hemoglobin.

Answer 4

All blood is pink. Oxygenated blood is bright pink, and de-oxygenated blood is darkish pink. It looks blue on your veins because of the fact the tissue between the blood and the exterior international bends the sunshine and makes it look blue. (like the ambience makes the sky look blue) The evidence that the blood on your veins isn't blue is this: in case you have blood drawn right into a syringe from a vein (or provide blood on the pink flow) it would not come into touch with air. it remains pink.

Answer 5

The color of blood is always within the red spectrum (bright red when oxygenated and a deep red maroon color when deoxygenated). Blood appears blue when viewed thru the skin because the red spectrum is absorbed more by the skin and blood than the blue spectrum. The blue spectrum is reflected back by the skin over the vein giving it a bluish cast.

Answer 6

From what I learned in school, the veins that are blue have blood that doesn't have oxygen in it. If they are red, they have oxygen in them. So when you cut a vein that is blue and the blood inside is exposed to oxygen, it turns red.

Answer 7

What you are seeing is a chemical reaction. The particles of blood are blue until they meet up with oxygen, then they turn red.
The veins are carrying blood without oxygen (blue) back to the heart and lungs to get more oxygen. The arteries are carrying red blood with oxygen to body parts for fuel. When you cut yourself, your blue blood meets the air and turns red.

Answer 8

It is red in the arteries because it is full of oxygen i.e. has just come from the lungs and is on its way to the organs and tissue. And the veins are blue because they carry the blood that is coming back from the organs and tissue to the lungs without oxygen, because the body used the oxygen.

Answer 9

Deoxygenated blood from Arteries looks blue arteries are deeper and larger vessels than veins... Blood that is oxygenated goes through the cardiovascular system, lungs bring oxygen into the body recirculates through the Veins. And that's why it looks red when it comes out.

Answer 10

Arteries carry pure blood from heart to various parts of the body. They contain oxygen which activates Haemoglobin, the red colouring pigment in blood. on contrary, Veins carry impure blood i.e. de-oxygenated blood, which doesn't have oxygen. Hence the red color is not visible. However when blood comes out, it gets oxygen from air and turns up into same colour as that of in arteries.