Write a note on erythrocytes.

Explanation

Erythrocytes are circular, biconcave, non-nucleated cells. The size is about 7 `mum` in diameter and 2.5 `mum` in thickness. There are about 5.1 to 5.8 million RBC's per cubic mm of blood in adult male and 4.3 to 5.2 million per cubic mm in adult female. This called total RBC count. The average life span is about 120 days. Cytoplasm of RBCs contain respiratory pigment called haemoglobin which helps in transport of oxygen and `CO_(2)`. RBCs transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs. They maintain blood pH as haemoglobin acts as a buffer. They also maintain the viscosity of blood.