Platelets are produced in the bone marrow, the same as red blood cells and most white blood cells. They are made from large bone marrow cells called megakaryocytes.
Platelet production, as well as megakaryocyte maturation, are regulated by the action of thrombopoietin, a hormone produced by the liver and kidneys. Each megakaryocyte produces between 1,000 and 3,000 platelets before it breaks down.
