Thrombocyte

anuclear, irregularly shaped disklike cell fragment shed in the marrow sinus and subsequently found in the peripheral blood where it functions in primary hemostasis as the first step of blood coagulation

Description
Thrombocytes are derived from megakaryocytes, either by rupturing of the large cells or by the continuous release of thrombocytes from megakaryocyte pseudopodia (cellular protrusions) into the blood. A thrombocyte contains granules in the central part (granulomere) and, peripherally, clear protoplasm (hyalomere), but no definite nucleus. It is about one-third to one-half the size of an erythrocyte. Syn platelet, blood disk, thromboplastid, elementary particle