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Etymology: Fr, small plate
anucleate blood cells, 1-3 μm in diameter. Platelets are formed from bone marrow megakaryocytes. Approximately one third of circulating platelets become temporarily sequestered in the spleen. Platelets are disk-shaped, contain no hemoglobin, and are essential for coagulation and in maintenance of hemostasis. The platelet count reference interval is 150,000-450,000/uL. Also called thrombocyte. Compare erythrocyte, leukocyte. See also thrombocytopenia, thrombocytosis.
thrombocytesdisc-like components of mammalian BLOOD, consisting of non-nucleated cytoplasmic fragments of large bone-marrow cells 3 μm in diameter called megakaryocytes that have entered the blood circulatory system. Platelets play an important part in BLOOD CLOTTING.
Fragments of a large precursor cell (a megakaryocyte) found in the bone marrow. These fragments adhere to areas of blood vessel damage and release chemical signals that direct the formation of a blood clot.