New Blog 1: Is Blood Really Blue

Saturday, 13 October 2012

Is Blood Really Blue

Red blood cells are always red. Since RBCs make up about 40-45% of our blood, the blood is red. Red blood cells are red because they have a protein called hemoglobin which contains iron. Iron likes to bind oxygen. Oxygen combined with iron is red. The more oxygen iron has bound to it, the redder it is.It is true that some persons have "iron poor blood". In this case their red blood cells are less red than normal, but they are still red. The iron in the hemoglobin of red blood cells is what carries oxygen to every tissue in the body.Why some people may think that blood can be blue is probably because of the color of our veins, which may be visible near the skin's surface. They appear blue because they do not get as much oxygen as the other tissues. When the red blood cells go to the lungs, the iron in them picks up oxygen. Blood then goes to the heart and then to the rest of the body through vessels called arteries. The arteries appear reddish as do many other organs, because the iron in the blood gives up its oxygen to the cells that need it as the red blood cells travel throughout the body. By the time the blood is back on its way to the heart and then to the lungs it has less than half as much oxygen as it did before. The veins, therefore, do not get as much oxygen as the other tissues and they appear bluish.