Vérlemezkek

Vérlemezkek, also known as thrombocytes, are tiny, irregular-shaped cell fragments found in the blood of mammals. They are not true cells in the sense that they lack a nucleus and most organelles. Instead, they are derived from large bone marrow cells called megakaryocytes. Vérlemezkek play a crucial role in hemostasis, the process of stopping bleeding. When a blood vessel is injured, vérlemezkek aggregate at the site of the wound. They adhere to the damaged endothelium and to each other, forming a platelet plug. This plug acts as a temporary barrier, reducing blood loss. In addition, vérlemezkek release a variety of factors that promote blood clotting. These factors initiate a cascade of enzymatic reactions that ultimately lead to the formation of fibrin, a protein that reinforces the platelet plug and forms a stable clot. The normal count of vérlemezkek in human blood ranges from 150,000 to 450,000 per microliter. A deficiency in vérlemezkek, known as thrombocytopenia, can lead to increased bleeding and bruising. Conversely, an abnormally high count, called thrombocytosis, can increase the risk of blood clots.