Platelets, also known as thrombocytes, are regularly-shaped clear cell fragments (cells that do not have a nucleus containing DNA) made in the bone marrow along with other kinds of blood cells and are the smallest of the 3 major types of blood cells. They travel through the blood vessels and stick together (clot) to stop any bleeding that may happen if a blood vessel is damaged. The average lifespan of a platelet is normally just 5 to 9 days.

Attribution: Straight Talk Foundation