Question

How Can RBCs be called cells if they don't have nucleus and many other vital cell organelles?

Answer 1

The cells from which RBCs develop during erythropoiesis are just like any other cell and have nucleus and other cell organelles. Later, during maturation RBCs lose these organelles and nucleus which is, in fact, an adaptation in order to accommodate larger amount of haemoglobin the respiratory pigment and increase the oxygen binding efficiency. Thus, RBCs are rightly called red blood cells. They are also called erythrocytes as these are cells (cytes) red (erythros) in colour, and red blood corpuscles as the float freely in a medium.