The Main Functions Of Platelets in Blood
PLATELETS are round or oval shaped cells with biconcave surface. They are tiny blood cells that help your body form clots to stop bleeding . If one of our blood vessels gets damaged, it sends out signals that are picked up by platelets . The platelets or thrombocytes then rush to the size of damage and form a plug , or cut to repair the damage . They are roughly one forth of the size of a RBC. Normal platelets count is 2 -5 lakh per cu mm of blood. Platelets do not have a nucleus by their cytoplasm contain distinct granules .
PRODUCTION OF PLATELETS
Platelets are produced in the bone marrow, the same as the red cells and most of the white blood cells. Platelets are produced from very large bone marrow cells called megakaryocytes. As megakaryocytes develop into giant cells, they undergo a process of fragmentation that results in the release of over 1,000 platelets per megakaryocyte. The dominant hormone controlling megakaryocyte development is thrombopoietin (often abbreviated as TPO) .
READ MORE : Main Structure And Function Of Red Blood Cells
It is a large bone marrow cell with a lobulated nucleus responsible for the production of blood thrombocytes (platelets) which are necessary for the normal blood clotting .
Platelets are actually not true cells but merely circulating fragments of cells. But even though platelets are merely cell fragments, they contain many structures that are critical to stop bleeding. They contain proteins on their surface that allow them to stick to breaks in the blood vessel wall and also to stick to each other. They contain granules that can secrete other proteins required for creating a firm plug to seal blood vessel breaks. Also platelets contain proteins similar to muscle proteins that allow them to change shape when they become sticky.
They are shaped like a plate, therefore their name. When platelets are stimulated by a break in the blood vessel wall they change shape as shown in the other three pictures. They become round and extend long filaments. They may even look like an octopus, with long tentacles reaching out to make contact with the broken blood vessel wall or with other platelets. With these long filaments, platelets then form a plug to seal the broken blood vessel.
FUNCTION OF PLATELETS OR THROMBOCYTES
1. THROMBOPLASTIN liberated from platelets is essential for clotting .
2. Close minute lesions in the walls of bloods vessels .
3. Platelets aid in body’s defence mechanism against bacteria.
4. They release some substances like histamines and serotonin.
Thromboplastin is a plasma protein aiding blood coagulation through catalyzing the conversion of prothrombin to thrombin.
THROMBOCYTOPENIA [Thrombocytopenia is a condition in which you have to low blood platelets count.] Platelets are colourless blood cells that help blood clot . Platelets stop bleeding by clumping and forming plugs in blood vessels injuries.