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noun, plural: promonocytes

An immature monocyte arising from a monoblast


Hematopoiesis is the process of forming new blood cellular elements in vertebrates. It begins with a multipotent stem cell, a hemocytoblast, which gives rise to a common myeloid progenitor cell (CMP). The CMP, in turn, gives rise to granulocyte-monocyte colony forming units (CFU-GM), also called granulocyte-macrophage progenitor. The CFU-GM may partially differentiate into CFU-G (precursor in myelocyte-granulocyte series) or CFU-M (precursor in monocyte-macrophage series). The CFU-GM serves as the precursor for monoblasts and myeloblasts.

In the monocytic series, the monoblast is the precursor cell for promonocyte, an immature monocyte. Compared with a monoblast, a promonocyte would be slightly smaller. One of the distinctive characteristic of a promonocyte is the nucleus that is ceribriform. This is due to delicate nuclear indentations and folds. There may be one or two nucleoli. It has a coarse chromatin structure but finer than that of a mature monocyte. The cytoplasm is slightly basophilic with fine azurophilic granules.


  • premonocyte

See also:

Related form(s):

  • promonocytic (adjective, of, pertaining to, or relating to a promonocyte)