n. the process of production of *granulocytes, which normally occurs in the blood-forming tissue of the *bone marrow. Granulocytes are ultimately derived from a *haemopoietic stem cell, but the earliest precursor that can be identified microscopically is the *myeloblast. This divides and passes through a series of stages of maturation termed respectively *promyelocyte, *myelocyte, and *metamyelocyte, before becoming a mature granulocyte. See also haemopoiesis.
n. an immature *granulocyte (a type of white blood cell), having a kidney-shaped nucleus (compare myelocyte) and cytoplasm containing neutrophil, eosinophil, or basophil granules. It is normally found in the blood-forming tissue of the bone marrow but may appear in the blood in a wide variety of diseases, including acute infections and chronic *myeloid leukaemia. See also granulopoiesis.... metamyelocyte
n. the earliest identifiable cell that gives rise to a *granulocyte, having a large nucleus and scanty cytoplasm. It is normally found in the blood-forming tissue of the bone marrow, but may appear in the blood in a variety of diseases, most notably in acute myeloblastic *leukaemia. See also granulopoiesis. —myeloblastic adj.... myeloblast
n. an immature form of *granulocyte having an oval nucleus (compare metamyelocyte) and neutrophil, eosinophil, or basophil granules within its cytoplasm (compare promyelocyte). It is normally found in the blood-forming tissue of the bone marrow, but may appear in the blood in a variety of diseases, including infections, infiltrations of the bone marrow, and certain leukaemias. See also granulopoiesis.... myelocyte
(premyelocyte) n. the developmental stage of a *granulocyte (a type of white blood cell) between the *myeloblast and the *myelocyte. It has abundant cytoplasm that, with *Romanowsky stains, appears blue with reddish granules. Promyelocytes are normally found in the blood-forming tissue of the bone marrow but may appear in the blood in a variety of diseases. See also granulopoiesis.... promyelocyte
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