od is made up of three main component CELLS:Red Blood Cells Red blood cells, called erythrocytes, comprise about 40 to 50 percent of the overall blood volume. Levels vary for males and females, with men having 5 to 6 million erythrocytes per cubic millimeter of entire blood and women having 4 to 5 million per cubic millimeter. Red blood cells live for approximately 120 days prior to being changed by new cells produced in the bone marrow. The red color originates from a pigmented particle, called hemoglobin, inside red blood cells. Red blood cells carry oxygen throughout the body and provide carbon dioxide from tissues to the lungs to be exhaled.White Blood CellsWhite blood cells, also called leukocytes, are much fewer in number than red blood cells. There are 5 different types of white blood cells that collaborate to protect the body by attacking foreign intruders, consisting of bacteria, viruses and tumors. The most typical type of white blood cells are called neutrophils. All types of white blood cells are produced in the bone marrow.PlateletsPlatelets, also called thrombocytes, are cell fragments instead of entire cells. They clump TOGETHER and form blood clots after an injury. Clots FUNCTION as plugs to stop bleeding and function as a base for new tissue growth and recovery in the injured area. Certain blood-thinning medications reduce the risk of abnormal blood clots by interfering with platelet function.