Why is blood red in colour but the vein is green?
94518
All blood is red. Blood with oxygen has a lighter/brighter color, while blood without oxygen is more of a purpleish tint. It does not change color completely from blue to red. This is a common misconseption given from the fact that many charts use red and blue to show clearly which blood streams are which. The vein is greenish because of the many colors in your body combined. The skin, blood itself, and many other things contribute to this. I don't know about live veins, but I know the ones in stuff like meat are white, not green.
974165
When you suffer from a lack of oxygen, the color of blood seems darker. It is also the case for venous blood which seems dark. In contrast oxy hemoglobin seems more bright as is arterial blood rich in oxygen.
268161
you may have spider veins:\n\nWhat are varicose veins and spider veins?\nVaricose veins are enlarged veins that can be flesh colored, dark purple or blue. They often look like cords and appear twisted and bulging. They are swollen and raised above the surface of the skin. Varicose veins are commonly found on the backs of the calves or on the inside of the leg. During pregnancy, varicose veins called hemorrhoids can form in the vagina or around the anus.\n\nSpider veins are similar to varicose veins, but they are smaller. They are often red or blue and are closer to the surface of the skin than varicose veins. They can look like tree branches or spider webs with their short jagged lines. Spider veins can be found on the legs and face. They can cover either a very small or very large area of skin.\n\nWhat causes varicose veins and spider veins?\nThe heart pumps blood filled with oxygen and nutrients to the whole body. Arteries carry blood from the heart towards the body parts. Veins carry oxygen-poor blood from the body back to the heart. \n\nThe squeezing of leg muscles pumps blood back to the heart from the lower body. Veins have valves that act as one-way flaps. These valves prevent the blood from flowing backwards as it moves up the legs. If the one-way valves become weak, blood can leak back into the vein and collect there. This problem is called venous insufficiency. Pooled blood enlarges the vein and it becomes varicose. Spider veins can also be caused by the backup of blood. Hormone changes, inherited factors, and exposure to the sun can also cause spider veins.
908467
Almost all vertebrates use the iron compound hemoglobin as the oxygen-transporting compound in their blood. Oxygenated hemoglobin is bright red, unoxygenated darker red. Many invertebrates use a copper compound rather than an iron compound to transport oxygen, so their blood is blue-green. I believe there is some arctic fish which also has blue-green blood, for the same reason.
1181100
not necessarily...it could just be fluid retention. Your legs could be building up fluid throughout the day and at night with you lying flat it disperses. Is your leg hot and red looking and tight...this could be a sign of something more sinister...DVT.....either way if you are concerned go to your GP and get it checked to put your mind at rest if nothing else.
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.
770329
it has to do with the refraction of light. as ice is denser that water vapour that makes up regular clouds it refreacts at differing angles and densities hence that is why it is green.
939860
What do you mean green veins?  As in, your veins are bulging so we can see your blood (blue before oxidation?).  If so this is pretty normal for muscular people.  If you are worried, of-course see your doctor.
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.
65667
The color of blood is blue.
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."
589426
No, in general menstrual blood color can vary from bright red to an almost black color. This is normal. You will usually find that your periods will start a lighter color (more reddish) and then turn brown or black for the remainder of your periods. However, if your whole period is a brown or black color I would go to a doctor just to check it out.
898825
It doesn't turn red when it is exposed to oxygen.  It is red.  What you see through your skin is the color of the veins.\n\n\nIt turns out that hemoglobin has a red color to\nit and that oxygenated hemoglobin is bright red.  So in arteries blood\nappears to be bright red.  This is true inside and outside.  Outside of the\nbody the color actually fades a bit (becomes darker), because there is less\npressure to keep oxygen associated with the hemoglobin.  But if you cut an\nartery the blood squirting out will appear bright red.  Blood that is in\nveins, however, has very little oxygen associated with it and this yields a\ncolor that is much darker.  As you noted, because of having to look through\nthe skin at veins they actually take on a blue tint, but really the blood\ninside (and if you cut a vein) is just a deep shade of red.  You can also\nsee this in persons that have stopped breathing or have blood flow blocked\nto a specific area; they appear blue. (A condition referred to as cyanosis.)
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
996461
Believe it or not it is blue while it is still in our bodies. You can tell by looking at a place in your body where the skin is thin like the inside of your arm or on your inner wrist. Where there is a blood vessel there is a blue line. Then once the blood gets exposed to oxygen it turns red.
60350
I have looked and seen.\nThe blood of most animals you are familiar with is red.\n\nYou are most familiar with oxygenated blood which is bright red. When you cut yourself the blood that leaks out is in contact with oxygen in the air and becomes oxygenated.\n\nDeoxygenated blood is a darker red.\nThe deoxygenated blood in veins is NOT visible just by looking at your skin. What you are seeing is the colour of deoxygenated blood viewed through the layers of tissue of the vein walls.\n\n'Blue blood' does not exist except for convenience in diagrams to distinguish it from the oxygenated blood in other parts of the diagram. The other common misconception is the use of 'blue blood' to describe aristocracy - cut of their heads and there is lots of bright red blood!\n\nHOWEVER - there ARE some animals (but none you are likely to have heard of) that do have blue blood - the oxygen is carried on copper rather than on iron.
580546
Yes, of course, the agranulocyte appear more green than the granulocyte.