Platelets

Colorless, nucleus-free, and variously shaped blood platelets, 2-3 microns in diameter; on average, there are 250-350 million of them in 1 ml of blood. Platelets are produced in the bone marrow and live for about 8 days. Approximately one-third of them circulate in the blood, while the rest accumulate in the spleen. The main function of platelets is to participate in blood clotting. They adhere to the injured blood vessel walls and release thromboplastin, and can also stick together. The mineral calcium, vitamin K, and the protein called fibrinogen help platelets form a clot. Old and damaged platelets are phagocytosed in the spleen, liver, and bone marrow. Platelets are not complete cells because they lack a nucleus, but all the main biochemical processes (protein synthesis, carbohydrate and lipid metabolism, biological oxidations related to phosphorylation processes) occur in them.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė