Erythrocyte Differentiation
In the process of red blood cell maturation, a cell undergoes a series of differentiations. The following stages 1–7 of development all occur within the bone marrow:
- hemocytoblast a multipotent hematopoietic stem cell
- Common myeloid progenitor multipotent stem cell
- unipotent stem cell
- pronormoblast also commonly called proerythroblast or rubriblast.
- basophilic normoblast/early normoblast also commonly called erythroblast
- polychromatophilic normoblast/intermediate normoblast
- orthochromatic normoblast/late normoblast - Nucleus is Expelled before becoming a reticulocyte
- reticulocyte
The cell is released from the bone marrow after stage 7, and so of circulating red blood cells there are ~1% reticulocytes. After 1–2 days these ultimately become "erythrocytes" or mature red blood cells.
These stages correspond to specific appearances of the cell when stained with Wright's stain and examined by light microscopy, but correspond to other biochemical changes.
In the process of maturation a basophilic pronormoblast is converted from a cell with a large nucleus and a volume of 900 fL to an enucleated disc with a volume of 95 fL. By the reticulocyte stage, the cell has extruded its nucleus, but is still capable of producing hemoglobin.
Essential for the maturation of RBC'S are two vitamins: B12 and folic acid. Lack of either of these causes maturation failure in the process of erythropoiesis, which manifests clinically as reticulocytopenia, an abnormally low amount of reticulocytes.
Read more about this topic: Erythropoiesis