Definition:
Granulopoiesis and monopoiesis are the formation of granulocytes and monocytes in the bone marrow. The term myelopoiesis is also widely used. This latter term includes the formation of three cell lines (erythropoiesis, granulopoiesis, and thrombopoiesis) but has become synonymous for granulopoiesis.
All cells of granulopoiesis are granulated except for the first maturation stage (myeloblast). An increased rounding of the nucleus with segmentation in mature stages is also typical. The ratio of myelopoietic to erythropoietic cells in the bone marrow film is 3-4:1. The daily production of a 70 kg adult is approximately 100-150 x 109 granulocytes or 1-2 x 109/kg. If necessary, the production capacity can be increased10-fold. A mitotic pool (up to and including myelocytes) is different from a post-mitotic pool (from metamyelocytes on). These two pools usually have a quantitative ratio of 1:1.
Granulopoiesis:
Myeloblast --> promyelocyte --> myelocyte --> metamyelocyte --> band neutrophils --> segmented neutrophils.
Immature eosinophils --> mature eosinophils
Immature and mature basophils
Monopoiesis:
Monoblast --> promonocyte --> monocyte