Red blood cell also called erythrocyte, cellular component of blood. Carry oxygen from the lungs to the tissues through the circulatory system and contains hemoglobin, is responsible for the red color of the cells and the blood. The red cell develops in bone marrow.
Shape of red blood cells: human red blood cell is small, round and biconcave, it appears dumbbell-shaped in profile. The average red cell in humans lives 100–120 days; there are some 5.2 million red cells per cubic millimeter of blood in the adult human.
Erythrocytosis: - When count of red blood cells increased than normal, condition is known as erythrocytosis. This occurs due to:-
Lower red blood cell count caused by-
1) Cell count
2) Percentage of blood volume occupied by red blood cells
3) Blood type
4) Erythrocyte sedimentation rate