normoblast

A nucleated red blood cell, the immediate precursor of a normal erythrocyte in humans. Its four stages of development are: 1) pronormoblast, 2) basophilic n., 3) polychromatic n., and 4) orthochromatic n. See erythroblast. [normo- + G. blastos, sprout, germ]

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nor·mo·blast 'nȯr-mə-.blast n an immature red blood cell containing hemoglobin and a pyknotic nucleus and normally present in bone marrow but appearing in the blood in many anemias compare ERYTHROBLAST

nor·mo·blas·tic -.blas-tik adj

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n.

a nucleated cell that forms part of the series giving rise to the red blood cells and is normally found in the blood-forming tissue of the bone marrow. Normoblasts pass through three stages of maturation: early (or basophilic), intermediate (or polychromatic), and late (or orthochromatic) forms. See also erythroblast, erythropoiesis.

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nor·mo·blast (norґmo-blast) [normo- + -blast] 1. a term often used as a synonym of erythroblast, but sometimes specifically denoting nucleated cells in a normal course of erythrocyte maturation, as distinguished from megaloblasts (q.v.); when the term is used with this meaning, the developmental stages of the nucleated cells of the erythrocytic series (q.v.) are generally named pronormoblasts (proerythroblasts) and basophilic, polychromatophilic, and orthochromatic normoblasts (see under erythroblast). 2. orthochromatic erythroblast.