Blood is always red, never blue.

[hybop]

It seems the old misconception that blood is blue when it is deoxygenated will never die.

http://en.wikipedia.org/wiki/Blood

Human blood is red, ranging from bright red when oxygenated to dark red when not. It owes its colour to hemoglobin, a metalloprotein compound containing iron in the form of heme, to which oxygen binds. There exists a popular misconception that deoxygenated blood is blue and that blood only becomes red when it comes into contact with oxygen. Blood is never blue, but veins appear blue because light is diffused by skin. Moreover, 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.

[James]

So why do our lips turn blue when we die?

[Chris4]

Why do we lose 21 grams when we die?

[James]

Why do we lose 21 grams when we die?

That required a google search for me

[Poison]

I also think that deoxygenated blood is red. Maybe a darker red than oxygenated blood. Think that when you are giving blood for some lab tests, blood is taken from the vein. and it is dark red.

[Charlene]

People's lips sometimes turns blue because when the light is diffused by skin, the veins appear blue~

[MrMistery]

I read in a so called "scientific magazine" this just last week. i couldn't believe my eyes. Why can't people understand that biology can not dodge the laws of chemistry and hemoglogin can't turn blue!!!!

[clarence]

I read in a so called "scientific magazine" this just last week. i couldn't believe my eyes. Why can't people understand that biology can not dodge the laws of chemistry and hemoglogin can't turn blue!!!!

I agree. Biology is based further on the laws of chemistry and physics that underlies all matter, including carbon-based living organisms. The skin acts like a color filter, so veins, with deoxygenated blood, appear somewhat bluish.

Btw, what is that "scientific magazine" that says hemoglobin can turn blue? That's biochemically impossible.

[MrMistery]

It's called "Science for all". It is edited my the Discovery channel

[Bellion]

I done a 4- year course in PE including anatomical studies and my father is a doctor and i guarantee deoxygenated blood is Blue!

[Navin]

I think that this general misconception derives from within many of our textbooks.

If you look under the circulatory system section, you would find figures of the circulatory system where oxygenated blood is represented in red, whilst deoxygenated blood is represented in blue. (This is of course useful for differentiation sake, but it certainly can confuse a person to think that deoxygenated blood is blue. And of course, our veins do appear blue).

So, ya, I feel that textbooks are to blame to a certain extent for this misconception.

[kiekyon]

oxygenated blood carry 2 oxygen molecules, the (shape) of the molecules allows blue and green light to be absorbed and red light to be reflected hence giving it the red color. However, when the cell is fully deoxygenated then the conformation of the molecules allows light from the orange spectra to be absorbed and reflecting blue light giving blood a blue tinge.