The platelets are known as thrombocytes, which are not whole cells but rather fragments or pieces of cells. Some of the stem cells in the red bone marrow differentiate into large cells called megakaryocytes, which break up into small pieces that enter circulation. These small, oval, circulating pieces are platelets, which may last for 5 to 9 days, if not utilized before that. Thrombopoietin is a hormone produced by the liver that increases the rate of platelet production. A normal platelet count is 150,000 to 300,000/µl (Tortora at. el., 2006).