Megakariotsüüdid

Megakariotsüüdid are very large cells found in the bone marrow. They are the largest cells in the human body and are polyploid, meaning they have multiple sets of chromosomes. Megakariotsüüdid are the precursors to platelets, also known as thrombocytes. Platelets are small, irregular-shaped cell fragments that play a crucial role in blood clotting.

The process of megakariotütopoeesis, the development of megakariotsüüdid, is complex and occurs in the bone marrow. It involves several stages of cell growth and differentiation. Megakariotsüüdid undergo endomitosis, a process where DNA replication occurs without cell division, leading to their massive size and polyploid nature.

Once mature, megakariotsüüdid extend long cytoplasmic extensions called proplatelets into the blood sinusoids of the bone marrow. These proplatelets fragment into thousands of individual platelets, which are then released into the bloodstream. This process of platelet formation is called thrombopoiesis.

The number and function of megakariotsüüdid are regulated by a hormone called thrombopoietin. Thrombopoietin stimulates the production and maturation of megakariotsüüdid, thereby influencing the overall platelet count in the blood. Abnormalities in megakariotsüüdid can lead to various bleeding disorders or thrombotic conditions.