noun, plural: erythropoieses
Hematopoiesis is the process of forming new blood cellular elements in vertebrates. The process starts at hemocytoblast, which is a multipotent hematopoietic stem cell. It gives rise to both lymphoid and myeloid stem cells. The myeloid stem cells, in particular, are progenitor cells that give rise to erythrocytes (as well as to granulocytes, monocytes, and megakaryocytes). Hematopoiesis leading to the production of an erythrocyte is referred to as erythropoiesis. Erythropoietin is the hormone that helps regulate erythropoiesis.
The stages of erythropoiesis are as follows: (1) A hemocytoblast gives rise to a common myeloid progenitor cell (CMP). (2) The CMP gives rise to CFU-e ( the colony forming unit that leads to the formation of erythrocytes) (3) The CFU-e develops into a proerythroblast (or a pronormoblast) (4) The proerythroblast (or pronormoblast) develops into an erythroblast (or normoblast). Both the proerythroblast and the erythroblast are nucleated red blood cells. (5) The erythroblast (or normoblast) develops into a reticulocyte. To become one, an erythroblast would undergo three stages: early, intermediate, and late. The erythroblast in the early stage is described as basophilic. The one in the intermediate stage is described as polychromatic (or polychromatophilic). The erythroblast in the late stage is described as orthochromatic (or orthochromatophilic). In humans and other mammals, the orthochromatic erythroblast (or normoblast) exudes its nucleus. It turns into an anucleated polychromatic erythrocyte (also called a reticulocyte). (6) The reticulocyte, which is an immature erythrocyte, possesses a reticular network of RNA. This cell develops into a fully mature erythrocyte by losing the filamentous RNA in about two days after its release from the bone marrow to the peripheral blood. Reticulocytes are still capable of producing hemoglobin. (7) An erythrocyte is a mature red blood cell with hemoglobin-rich cytoplasm and whose main function is to transport respiratory gases, chiefly oxygen. Folic acid and cobalamin are the essential vitamins to cause the maturation of erythrocytes.