Megakaryotsüüdid

Megakaryotsüüdid are very large bone marrow cells that are the source of platelets. These cells are multinucleated, meaning they have more than one nucleus, and their cytoplasm is filled with granules. Megakaryotsüüdid originate from hematopoietic stem cells, which are responsible for forming all blood cell types. The process of megakaryocyte development, known as megakaryocytopoiesis, is complex and involves several stages of maturation. As megakaryotsüüdid mature, they undergo significant growth in size and their DNA content increases without cell division. This unique characteristic allows them to produce a large number of platelets. Once fully mature, megakaryotsüüdid extend long cytoplasmic projections called proplatelets into the blood vessels of the bone marrow. These proplatelets fragment, releasing thousands of small, anucleated platelet cells into the circulation. Platelets play a crucial role in hemostasis, the process of blood clotting, and also participate in inflammatory and immune responses. The number and function of megakaryotsüüdid and their resulting platelets are tightly regulated by various growth factors, cytokines, and signaling pathways.