RBC Development - 1/4 Proerythroblast
The earliest proerythroblast is virtually indistinguishable from other “blast”cells e.g., myeloblast, lymphoblast, monoblast, etc. The “early” proerythroblast has a euchromatic nucleus with nucleoli; the cytoplasm is light blue and without granules. The “later” proerythroblast has a slightly more heterochromatic nucleus with nucleoli; the cytoplasm is decidely basophilic because of the newly synthesized ribosomes.