It is located inside the veins and arteries throughout the body, which together form the bloodstream. But if a break in the bloodstream occurs, such as a cut or even a small tear in an artery, escaped whole blood can be dangerous to the cells nearby, largely because of the pressure it can exert on them. The normal amount of blood in a human by weight is about 10 to 12 pounds in a person weighing around 150 pounds. A man has more blood than a woman of the same weight. A 150-pound man has about 11 or 12 pints of blood by volume, while a woman of that weight has only 8 or 9 pints and a woman weighing less has even less, with 7 pints about the average.
Blood is constantly on the move.
In 20 seconds a specific drop of blood can circulate completely from the heart , through the body, and back to the heart. That is because blood travels at an average rate of 0.7 miles per hour. Role Different parts of the blood have different functions. The red color of blood comes from erythrocytes, commonly known as red blood cells. Unlike true cells, erythrocytes lack nuclei and internal structure.