Normoblast
An normoblast is a type of red blood cell which still retains a cell nucleus. It is the immediate precursor of a normal erythrocyte (by opposition to the megaloblasts being an abnormal precursor).
Nomenclature
The term normoblast is sometimes used as a synonym for erythroblast, but at other times it is considered a subcategory. In the latter context, there are two types of erythroblasts:
- "normoblasts" - develop as expected
- "megaloblasts" - unusually large erythroblasts that can be associated with vitamin B12 deficiency (as in pernicious anemia) or folic acid deficiency (collectively called megaloblastic anemia)
Development
There are four stages in the development of a normoblast.
_diagram.png)
A comprehensive diagram of human hematopoiesis
| Illustration | Description | Image |
 | Pronormoblast | |
 | Basophilic normoblast |  |
 | Polychromatic normoblast (also polychromatophilic) |  |
 | Orthochromatic normoblast (also orthochromatophilic) |  |
Additional images
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Hematopoiesis
See also
External links
- Normoblasts at the US National Library of Medicine Medical Subject Headings (MeSH)
- Histology image: 01804loa – Histology Learning System at Boston University - "Bone Marrow and Hemopoiesis bone marrow smear, erythroblast series with proerythroblast "
- Histology at uiowa.edu
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