Prof. J.P.N. Mishra
Red blood cells (RBCs) are biconcave discs, which means their centers are thinner than their edges and diameter of about 7.5 pm. Red blood cells are the only human cells without nuclei. Their nuclei disintegrate as the red blood cells mature and are not needed for normal functioning (Fig. 1-11).
A normal RBC count ranges from 4.5 to 6.0 million cells per micro litter (ml) of blood. RBC counts for men are often toward the high end of this range; those for women are often toward the low end. Another way to measure the amount of RBCs is the haematocrit. Because RBCs are by far the most abundant of the blood cells, a normal haematocrit range is just like that of the total blood cells: 38% to 48%. Both RBC count and haematocrit (Hct) are part of a complete blood count (CBC).
