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The cell ceases its growth at 4N, 8N or 16N, becomes granular, and begins to produce platelets. [6] Thrombopoietin plays a role in inducing the megakaryocyte to form small proto-platelet processes. Platelets are held within these internal membranes within the cytoplasm of megakaryocytes. There are two proposed mechanisms for platelet release.
The megakaryoblast is a platelet precursor that undergoes endomitosis to form megakaryocytes that have 8 to 64 nuclei. Megakaryocytes shed platelets into the bloodstream. β1-tubulin microtubules, which are found in megakaryocytes, facilitate this process of shedding platelets into the bloodstream. [5]
The promegakaryocytes continue the process of endomitosis, which results in the formation of granular megakaryocytes as the nucleus forms lobes with increased volumes. The megakaryocytes release the platelets into the blood stream. [8] The process of platelet production, beginning with the formation of megakaryoblasts, takes about 7 days.
The platelet-rich plasma (PRP) is removed from the red cells, then centrifuged at a faster setting to harvest the platelets from the plasma. In other regions of the world, the unit of whole blood is centrifuged using settings that cause the platelets to become suspended in the " buffy coat " layer, which includes the platelets and the white ...
Different cells can release microvesicles from the plasma membrane. Sources of microvesicles include megakaryocytes, blood platelets, monocytes, neutrophils, tumor cells and placenta. Platelets play an important role in maintaining hemostasis: they promote thrombus growth, and thus they prevent loss of blood
The CFU-GEMM cell is capable of differentiating into white blood cells, red blood cells, and platelets, all of which are normally found in circulating blood. [4] It has been suggested that eosinophils do not derive from the common myeloid progenitor in humans. [5] Chart showing the lineages of hematopoiesis.
Platelets, or thrombocytes, are very small, irregularly shaped clear cell fragments, 2–3 μm in diameter, which derive from fragmentation of megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors.
Megakaryocyte–erythroid progenitor cells must commit to becoming either platelet-producing megakaryocytes via megakaryopoiesis or erythrocyte-producing erythroblasts via erythropoiesis. [ 2 ] [ 3 ] Most of the blood cells produced in the bone marrow during hematopoiesis come from megakaryocyte–erythroid progenitor cells.