plateleti

Platelets, also known as thrombocytes, are small, irregularly shaped cell fragments critical to the process of blood clotting and wound healing. They are produced in the bone marrow from larger cells called megakaryocytes and circulate in the bloodstream, playing a vital role in maintaining hemostasis—the cessation of bleeding.

Typically measuring 2-3 micrometers in diameter, platelets lack nuclei and are composed mainly of cytoplasm enclosed by a cell membrane. They contain granules filled with clotting factors, enzymes, and signaling molecules essential for their function. When a blood vessel is injured, platelets rapidly adhere to the exposed collagen fibers at the injury site, activated by signals such as thrombin and ADP, they change shape and release their granule contents.

This activation process leads to the recruitment of additional platelets, forming a platelet plug that temporarily seals the wound. Concurrently, they facilitate the coagulation cascade by providing surface sites for clotting factor interactions, culminating in the formation of a fibrin mesh that stabilizes the blood clot. After the repair is complete, platelets are involved in processes to resolve the clot and restore normal blood flow.

A normal platelet count ranges from approximately 150,000 to 450,000 platelets per microliter of blood. Abnormal platelet levels can cause bleeding disorders, such as thrombocytopenia (low platelet count), or increase the risk of thrombosis (clot formation). Platelet function and count are routinely assessed in blood tests to diagnose and monitor various hematological and coagulation disorders. Their essential role in hemostasis makes them a critical component of the circulatory and immune systems.