Platelet: S are blood cells

Platelets are blood cells that form clots to stop bleeding. Learn about their origin, shape, granules, receptors, and role in hemostasis and immunity. platelet , colourless, nonnucleated blood component that is important in the formation of blood clots (coagulation). Platelets are found only in the blood of mammals. Platelets are formed when cytoplasmic fragments of megakaryocytes, which are very large cells in the bone marrow, pinch off into the circulation as they age. They are stored in the spleen. Some evidence suggests platelets may also be produced or stored in the lungs, where megakaryocytes are frequently found. Platelets play an ... A platelet count measures the average platelet level in a person’s blood. Platelets are crucial to wound healing and clotting, and abnormal levels can indicate various health conditions. Learn what a platelet count test reveals about your health. Discover causes, symptoms, and treatments for low and high platelet levels, plus tips to improve platelet count naturally.