why is blood red but the vein is green?
156204
I don't believe that guy called her a moron for giving the right answer. Yes blood without oxygen is blue but it may appear green due to you looking at it through your skin. I'm sure you've seen someone with blue lines on their body. When blood becomes oxygenated...the Fe is pulled to the center of the heme ring. It's actually this conformational change that produces the red color. Not rust. Also to comment. The Fe is contained within the porphyrin ring but not in a flat structure. It is partially off center and is pulled more equally within the ring structure with the addition of oxygen. If you looked it up you'd know I wasn't making **** up. Although i do apologize for the blue comment. But we see blue because of the absorption of light at the surface of our skin. At least while the blood is stil in circulation. You need to be less critical. Yes all of them are red but to the naked eye under the skin they clearly appear blue. It's not total "bullocks" for someone to assume such. The intelligent should learn to be teachers not arrogant tactless shrews.
461959
It is blue when the blood does not have oxygen in it.  Once blood is drawn though, it hits the oxygen and turns red.
271931
I've often wondered this myself:\n\n"Why are veins green?\n\nIn the light blood appears red because most colors are absorbed except for red, which bounces back from the blood. If a filter that blocks the reflected color is positioned between the blood and the eyes of the person watching, the perceived color changes. In the case of humans, the skin serves as a filter for the color red, and the remaining color ends up being green, and relative levels of oxygenated iron (FE+O) and CO2 in the blood cause different color spectra to be reflected. High xxygen reflects red and high CO2 reflects blue, which mixed with the yellowish color of the fat and/or skin ends up showing as green."
252838
human hemoglobin contains one atom of iron in its core. This iron plus oxygen turns red; plus carbon dioxide turn dark red; plus carbon monoxide turns very bright red. So, the color of blood comes from the iron in the hemoglobin molecule AND the compound binding to it. By the way, some crab species have copper in their hemoglobin instead of iron, so their blood is... BLUE!
901244
Sometimes menstrual blood can appear bright red, sometimes it is dark & clotted-looking.  I wouldn't worry about it unless your period lasts longer than usual, or if it is unusually heavy for several hours (soak through a pad or tampon in an hour or less.)  If something seems seriously wrong, check with a doctor.
922148
That is blood pooling under the skin from the needle puncturing your vein...this too shall pass...your body will re-absorb the blood.
821922
it depends how much blood you have, if there's a lot, then it will appear a brick red color, but if its not so much, then it looks bright red untill it dries, then its brick red once again
474322
Red is blood of all creatures.\n\nGreen is seen as tranquil to go in peace.
1038235
Yes . If they have green blood
799464
Blood does not need oxygen to be red.  Blood is never blue.  Just because a hose is green, it doesn't mean the water coming out will be green as well. (referring to veins)
224868
fisrt purple then back to blue \n\nthe chemical reactions that occur durring oxygen deporvation would be the same causing blood vessels to flush (turning us red- them blue) then upon oxygen deprovation in the bloodstream the hemoglobin would loose its red appearance giving the blue tint (so blue skin would stay blue)\n\nThat is of course assuming smurfs where REAL !! and had simalar physiology to existing life forms
956109
In humans and other hemoglobin-using creatures, oxygenated blood is bright red. This is due to oxygenated iron in the red blood cells. Deoxygenated blood is a darker shade of red, which can be seen during blood donation and when venous blood samples are taken. However, due to an optical effect caused by the way in which light penetrates through the skin, veins typically appear blue in color. This has led to a common misconception that venous blood is blue before it is exposed to air. Another reason for this misconception is that medical charts always show venous blood as blue in order to distinguish it from arterial blood which is depicted as red on the same chart.
539773
No, this is a very common myth. Blood is always red. When in an oxygen poor stage it assumes a red color that is not as intense as the red of the oxygen rich stage. The blue color comes from looking at your deoxygenated blood through layers of skin as well as the veins.
504422
First off ignore those claiming that the blood in your veins is blue. The blood  everywhere in your body is red, always. All the time. It is never blue. Any blue colour is an illusion it is just an illusion.. Blood fresh from the lungs in bright red, blood in the veins is dark red. But blood is never any colour but red unless you have been poisoned and are about to die.\n\nThe blood that you can see in the veins under your skin appears to be blue because the skin and the vein itself absorbs red and yellow light preferentially. That means that only the blue light returns to your eye. But it is entirely an illusion, and the blood in the veins is a dark red colour.\n\nAnyway, the reason that the blood is red is because it contains red blood cells, and red blood cells in turn are packed with a molecule called haemoglobin. Haemoglobin is a red colour, and that is what makes blood red.
1159357
the blood in your body is red. the appearance of the blue is the veins being close to the surface.\n\nBlood is *never* blue.  Blood is described as dark red (venous) or bright red (arterial).  Our veins look blue because we are looking at them *through* our skin.  The blood inside them is dark red and it doesn't reflect light very well. The blood you see when you get hurt is usually venous blood.
210583
I dont know about nerves,but the veins(the green tubes which can be seen just under our skin behind our wrists)are green coz they carry DEOXYGENATED blood.
361108
Blood is a liguid specially formulated to carry to every living cell of the body all the things essential to life - oxygen and other gases, iron and other minerals etc. It also helps to carry waste and toxins to organs that process them for disposal (lungs, liver, spleen etc). \n\nIn humans and the bigger animals its appearance is pretty obvious (red, gooey stuff), but in many small creatures and insects it is more mixed up with the general chemistry of the creature. They have less developed vascular systems (arteries and veins) and they don't process exactly the same chemicals as us so their 'blood' is a different colour and texture.\n\nFinally, even in humans there is more than one system for transporting stuff around - we also have our lymphatic system which contains a clear fluid called 'lymph'. It is vital in helping us to fight infections and when its working hard in our defence thats when you get swollen glands - these are the lymph nodes - factories for fighting the nasties transported there by the lymph - you have these all over, but especially in your throat, under your arms, in your groin etc. Its what the doctor feels for when you have a temperature.\n\nFascinating stuff!