what changes in human erythrocyte during maturation?

Answer 1

The hormone erythropoietin interacts with immature erythroid cells (erythroid stem progenitors of CFU-E type) and stimulates their proliferation, syntheses of hemoglobin, and the enzymes involved in heme biosynthesis, that is, maturation and differentiation of erythroid progenitors. Low partial pressure of oxygen in venous blood (hypoxia) is another stimulator of erythropoietin synthesis.

Interacting with cell receptor, erythropoietin activates the transcription factor GATA-1, a key regulator of erythrocyte differentiation. GATA-1 stimulates syntheses of a -, b -globins, and the enzymes of heme biosynthesis. In addition, GATA-1 activates its own gene and gene of erythropoietin receptor (positive feedback). Heme, a -globin, and b -globin form hemoglobin, the major component of the mature erythrocyte.

Answer 2

What they said.

But more simply - as a committed stem cell (ie cell that is 'programmed' to become red cells) divides exponentially to produce your nucleated red cells it gets progressively smaller with each division. Under normal circumstances they divide up to 4 times producing approximately 16 cells each.

As the haemoglobin is synthsized, the cytoplasm goes from being Basophilic (takes up blue stain) to Eosinophilic (takes up red stain) and the nucleus gets smaller as the nuclear chromatin gets more condense. As a result th RBC reduces in size. When it leaves the bone marrow the nucleus is 'pitted' from the red cell so that only the haemoglogin is left.

This is then a polychromatic RBC or reticulocyte, in which reminant ribosomal RNA is still present from the removal of the nucleus. This gives the RBC a bluish hue when coloured with a Geimsa or Romanowsky stain. When the RBC is completely mature it looses the bluish hue giving a 'salmon pink' colour when coloured with the same stain.

Answer 3

It becomes smaller in size and changes from basophilic to eosinophilic,