5 Liters

Water, in a protein sense, salt and other substances, make up plasma, which, in kind, account for half of blood's design. A mammal's blood is red and bright, -from oxygen, when mixed inside. Because of an iron-filled kind of protein, Hemoglobin, it's red and glowing. Red and white cells fill the half, oxygen rides in small red rafts. Compared to white, the reds are many, born from marrow, good and plenty. Blood supplies glucose and acids, while carbon dioxide wastes are banished. Coagulation is the body's repair, as hormones message when damage is there. It regulates the body heat, hydro-mechanics, just like a machine. Blood makes 7% of your weight, red cells live 120 days. The white cells clot the blood on site, they help by killing parasites. White cells come in different types, some kill bacteria, and fungi, allergic reactions, virus cells, tumors, pathogens as well. If only we could go within, to see a white cell's origin. We could show our gratitude, for those that keep us strong like new. Our health is their only mission, their ranks are in the immune system. The heart drives blood throughout the body, from the ventricles, to the arteries. -Back to the heart and through the veins, ventricle, artery, lungs, you could say, the blood travels far, and this would be truth, it takes 30 seconds to complete it's route. Oxygen brought in must be spread around, While carbon dioxide is what's carried out. The vein is a valve containing the waste, which is pushed with help from muscles in legs. Arteries branch out as smaller roads called, Capillaries, just one cell thick is their wall. The blood must be slowed to allow the breakdown, of substances, nutrients, eat up the chow! Blood is classified in 200 groups, you inherit whichever your parents gave you. The most common kinds are "A" "B" and "O", Some have "A" or "B", and some people have both. It's important to know, should you need more blood, a bad combination will make it clot up. Blood brings to life almost every creature, -we could not be without, those...5...liters.