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Medical Term:


Pronunciation: plat'let


An irregularly shaped, disclike cytoplasmic fragment of a megakaryocyte that is shed in the marrow sinus and subsequently found in the peripheral blood, where it functions in clotting. A platelet contains granules in its central part (granulomere) and, peripherally, clear protoplasm (hyalomere), but no nucleus, is about one third to one half the size of an erythrocyte, and contains no hemoglobin.

Synonym(s): Bizzozero corpuscle, blood disc, elementary bodies2, elementary particle1, third corpuscle, thrombocyte, thromboplastid1, Zimmermann corpuscle

[see plate]

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