Question

How do red blood cells reproduce?

Answer 1

Red blood corpuscles are the most formed elements of the blood and are the most abundant cells in the human body. A unique feature of the RBC is the presence of a red oxygen carrying called hemoglobin in their cytoplasm.

Complete answer:
A single red blood cell is bounded by an elastic and semi permeable plasma membrane which enables it to squeeze through capillaries having a diameter less than its own. The mature red blood cells do not have nucleus which provides them more space to hold hemoglobin. Its oxygen consumption is very low due to lack of organelle which makes sure that it can supply more oxygen carried by hemoglobin to the tissue cells.
As the red blood cells lack cell organelles so they cannot reproduce or carry out cellular metabolism.
Formation of red blood corpuscles is called erythropoiesis. It occurs in the liver and spleen in the foetus and in the red bone marrow after birth.
About two million red blood cells are formed every second in the body and the formation of a single red blood cell takes about two days.
Human RBCs are functional in the blood for about 120 days. The RBC are destroyed by phagocytosis in the blood itself and in the liver and spleen. Their iron is returned to the red bone marrow for use in the synthesis of fresh hemoglobin. Their pigment is degraded to yellow pigment bilirubin which is excreted in bile and it also gives the pale yellow colour of the plasma.

Note: Proteins and irons are components of haemoglobin. Vitamin B12 and Folic acid stimulate erythropoiesis. Deficiency of any of these may cause anaemia. Excess of RBC is stored in the spleen.