Blood is living tissue that cleans and nourishes the human body while also fighting infections, healing wounds and performing many other vital functions for the human body. It is a fragile substance that cannot be manufactured and can only be stored for a very limited time. There is no substitute for blood. Donors are the only source of blood for patients who need it.
Blood can be separated into various components: red blood cells, white blood cells, plasma and platelets. Each component serves a different purpose for the human body. Red cells, white cells and platelets, made in the marrow of bones, fight infection, carry oxygen and help control bleeding. Plasma functions as a carrier for blood cells, nutrients, enzymes and hormones throughout the body.