Megaloblast

A megaloblast is an unusually large erythroblast that can be associated with Vitamin B₁₂ deficiency (as caused by pernicious anemia or dietary insufficiency) and/or folic acid deficiency (collectively called megaloblastic anemia). It is differentiated from a normoblast, which is a normally-sized erythroblast. This kind of anemia leads to macrocytes (abnormally large red cells). The cause of this cellular gigantism is an impairment in DNA synthesis which delays nuclear maturation and cell division. Because RNA and cytoplasmic elements are synthesized at a constant rate despite the cells' impaired DNA synthesis, the cells show nuclear-cytoplasmic asynchrony.

Additional images

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  Blood cell lineage

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  Hematopoiesis

See also

• Erythropoiesis
• Hemopoiesis
• Pluripotential hemopoietic stem cell

External links

• Pronormoblasts Presented by the University of Virginia
• Basophilic Normoblasts Presented by the University of Virginia
• Polychromatophilic Normoblasts Presented by the University of Virginia
• Orthochromatic Normoblasts Presented by the University of Virginia
• "Megaloblast" at Dorland's Medical Dictionary

• "Normoblast" at Dorland's Medical Dictionary

• "Erythroblast" at Dorland's Medical Dictionary

• 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