There is no substitute for human Blood. Blood makes up about 7 percent of your body's weight. An average adult has about 14 to 18 pints of Blood. One standard unit or pint of Blood equals about 2 cups.
Blood carries oxygen and nutrients to all of the body.
Blood carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. Blood fights against infection and helps heal wounds. The three main types of cells making up our Blood are the White Blood cells, Red Blood cells and Platelets. White Blood cells have a rather short life cycle, living from a few days to a few weeks. One drop of Blood can contain from 7,000 to 25,000 white Blood cells.