You are now at the beginning of the RBC Basics study
Much of what is known of red cell development has been
learned from careful morphologic observation of RBC
precursors in marrow and in in vitro culture. In culture
individual cells of variable maturity are stimulated to
grow, forming colonies. These are referred to as colony
forming units or burst forming units with the
suffix E for erythroid.
Although red cell development is generally observed by
cell morphology, there are sequential changes in protein
synthesis and expression which can be observed as
antigen expression, ie. Glycophorin A and transferrin
receptor or by Northern blot of messenger RNA expression, ie
globin chain expression.
As cells mature, from the most immature or blast cell to
the final mature stage, they undergo numerous biochemical,
structural and metabolic changes. The cytologic features of
cells, as observed on Wright's stained peripheral blood and
bone marrow smears, reflect such biochemical and structural
developments. The general features of cell differentiation
are common to most blood cells. Immature cells have
delicate, fine nuclear chromatin which gradually becomes
coarsely clumped or condensed. The size of the nucleus
decreases; nucleoli are reduced in number or lost completely
as in red cells. The nuclear shape which is initially round
or oval may become uniquely confirgured as in myeloid cells.
Mitotic competence is lost as cells differentiate.