what colour is blood???

Answer 1

Human blood is ALWAYS red. Really. Anyone who says it's blue is mistaken.

This is plainly obvious if you ever donate blood. Phlebotomists always take blood from veins, they are required to do it without exposing it to air, and it always looks red. Likewise, any surgeon (or sausage company) will tell you that all veins and arteries are pretty much clear.

Now, I know what some of you are thinking: 'Wait a minute - I can see some of my veins and they are clearly blue!'. It's okay. There are scientists who have wondered about that too:

In a recent piece of research, it was discovered that veinous blood looks blue only because it's surrounded by much redder blood. They could even reproduce the effect by surrounding red veinous blood with a pool of red oxygenated blood... the veinous blood looked blue when submerged!

And so it goes with other colours as well. Many people have pigments in their skin that can alter the apparent colour of veins and arteries underneath. But this hardly means that the blood actually IS different colours!

There are creatures in the world that do not have red blood - some have greenish-blue blood because they use copper atoms to attract oxygen instead of iron. It doesn't work anywhere near as well, unfortunately for all the octopi and mollusks out there.

Answer 2

Its red because of iron bound to organic haem to form haemoglobin. The red is due to the iron absorbing different wavelengths of visible light (i.e., blue, green etc), but not red so that's the colour you see.
Oxygenated blood is a different red from deoxygenated blood because the oxygen alters the way in which the iron interacts with visible light.

Some animals have blue blood because the use copper rather than iron, which absorbs red and orange but not blue, so that's the colour you see.

Answer 3

Human blood appears red, in actual fact it is a suspension of red cells in a straw coloured liquid (plasma) which gives it this appearance. The red cells are bright red when the Haemoglobin in them is oxygenated, a darker red when deoxygenated. Other animals blood can be different colours, crustacean blood is blue because it's compound to carry oxygen contains a copper based protein, rather than the iron based haemoglobin.

Answer 4

Oxygenated blood appears red but deoxygenated blood appears purple/blue.

Blood is however made up of blood cells and plasma.
The oxygenated red blood cells containing oxyhaemoglobin give it the red appearance. When it is just haemoglobin however it has the purple/blue appearance.

The cells are mixes with a yellowish fluid called plasma too with transports dissolved substances like glucose, urea, hormones, amino acids and minerals.

Hope that helps.

Answer 5

Arterial blood, coming straight from the heart, is bright read due to it's high levels of oxygen. Blood being sent back to the heart is darker, and blood that has left the body and is clotting is almost brown. Blood is red due to a pigment in red blood cells, which insects don't have, which is why they ooze a green substance when you stand on them! It's called haemolymph, and it carries blood around the body in an open circulatory system, basically it's being pumped around the body cavity without the restraint of veins, vessels and arteries.
There, I'm a mine of useless information!

Answer 6

Blood is blue until it comes out of your body. Then it is red because of the oxygen. That's why your veins are blue and when the blood comes out it is red.

Answer 7

Oxygenated blood is red, as it ha oxygen. However deoxygenated blood has more C02 than oxygen, as it is collecting waste gases from respiration. So that will be darker red/purple

Answer 8

Blood red!

Answer 9

Red

Answer 10

Dark blue/violet until it combines with too much oxygen and oxidizes then it becomes red.