Enucleated erythrocytes are present in the blood of all mammals, suggesting that enucleation provides an evolutionary advantage. ... These structural changes may be advantageous because, by decreasing cell rigidity, they facilitate the passage of red cells through the microvasculature and may minimize cardiac workload.

Is RBC enucleated?

Mammalian erythrocytes or red blood cells circulate without a nucleus. During development in the bone marrow, erythroid progenitors expand, mature and condense and expel their nucleus. ... All mammals possess enucleated red blood cells whereas erythrocytes of birds, reptiles, amphibians and fish all possess their nuclei.

Why human RBC is Biconcave?

RBCs are disc-shaped with a flatter, concave center. This biconcave shape allows the cells to flow smoothly through the narrowest blood vessels. ... Many RBCs are wider than capillaries, but their shape provides the needed flexibility to squeeze through.