Megakaryocyte

Megakaryocyte is a large bone marrow cell with a lobulated nucleus responsible for the production of blood thrombocytes (platelets), which are necessary for normal blood clotting. Megakaryocytes usually account for 1 out of 10,000 bone marrow cells but can increase in number nearly 10-fold during the process of thrombopoiesis. They are derived from hematopoietic stem cells in the bone marrow.

Structure

Megakaryocytes are 10 to 15 times larger than a typical red blood cell. They have a large, lobulated nucleus, violet granules in their cytoplasm, and demarcation membranes which outline platelet territories.

Function

The main function of the megakaryocyte is to produce platelets. This process is regulated by the hormone thrombopoietin. Megakaryocytes also contribute to homeostasis by producing a variety of substances that can promote inflammation and wound healing.

Clinical significance

Abnormalities in the number or function of megakaryocytes can lead to a variety of diseases. For example, a decrease in the number of megakaryocytes can lead to thrombocytopenia, a condition characterized by low platelet count. Conversely, an increase in the number of megakaryocytes can lead to thrombocytosis, a condition characterized by a high platelet count.

See also

• Thrombopoiesis
• Hematopoietic stem cell
• Thrombocytopenia
• Thrombocytosis

Megakaryocyte

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  WVSOM Megakaryocytes with arrows
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  Illustration of blood cell lineage
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  Platelets release in mature megakaryocytes