Blood Flow Accelerator The entirety of the cells found in the blood originate from bone marrow. They start their life as immature microorganisms, and they develop into three primary sorts of cells—RBCs, WBCs, and platelets. Thusly, there are three sorts of WBC—lymphocytes, monocytes, and granulocytes—and three primary kinds of granulocytes (neutrophils, eosinophils, and basophils). See them in real life in "Meet the platelets".