Megakaryocyte, Thrombocyte & Platelet
Our blood contains several different types of cells suspended in plasma (the liquid). The cells are created in the bone marrow by blood stem cells. The cells consists of three groups: white blood cells (abbreviated as WBC), which are leukocytes; red blood cells (RBC), which are erythrocytes); and platelets, which are thrombocytes.
Megakaryocytes are derived from hematopoietic stem cell precursor cells in the bone marrow. Megakaryocytes are primarily produced by the liver, kidneys, spleen, and bone marrow, but they may also be found in other organs, such as the lungs, and in the peripheral blood.
Megakaryocytes are multi-potent stem cells that live in the marrow sinusoids, and are capable of producing all types of blood cells depending on the signals they receive. Megakaryocytopoiesis is the process by which the bone marrow progenitor cells develop into mature Megakaryocytes, which in turn produce platelets.
The production of platelets by Megakaryocytes requires an intricate series of remodeling events that result in the release of thousands of platelets from a single Megakaryocytes. Generally speaking, Megakaryocytes and platelets production is regulated by thrombopoietin, which is a hormone produced by the kidneys and liver.
Each megakaryocyte cell can produce 5,000 to 10,000 platelets (thrombocytes) before being depleted.
Megakaryocytes are responsible for wound healing and processes such as hemostasis (equilibrium in the blood).
The word 'thrombocyte' is derived from throm, to mean blood clot, and cyte, to mean cell. Platelets function with coagulation factors to stop bleeding by clumping together to clot blood vessel injuries. Platelets have no cell nucleus; they are fragmented off of Megakaryocytes.
The normal platelet county ranges from 150,000 to 450,000 platelets per microliter of blood.
Thrombocythemia is a condition in which a person's platelet county is too high.
Thrombocytopenia is a condition in which a person's platelet count is low, if the cause is unknown, or Thrombocytosis, if the cause is related to another disease or condition causing it.