What are erythrocytes; where are they produced? What do erythrocytes lose late in their genesis; what do they gain? How numerous are erythrocytes? What is their average life-span; where are they destroyed?
Erythrocytes, small, biconcave, disc-shaped cells, are produced from rapidly dividing connective tissue cells in red bone marrow. Late in their genesis, erythrocytes lose their nuclei and gain the oxygen carrying pigment hemoglobin. Erythrocytes are so numerous that there are approximately 5 million per cubic millimeter of blood. Each erythrocyte normally survives 120 days before being destroyed by phagocytic cells in the liver and spleen which together destroy over 2 million red blood cells every minute.
