Erythrocytes (Red Blood Cells - RBCs):
- RBCs are the most abundant cells in blood, with an average of 5 to 5.5 million per mm³ in a healthy adult man.
- They are produced in the red bone marrow and lack a nucleus in most mammals.
- Erythrocytes are biconcave in shape and contain hemoglobin, a red-colored, iron-containing protein crucial for oxygen transport.
- Hemoglobin enables RBCs to carry oxygen from the lungs to tissues and organs, playing a vital role in cellular respiration.
- The average lifespan of RBCs is approximately 120 days, after which they are removed by the spleen.
- Function: Erythrocytes primarily function in oxygen transport, facilitated by hemoglobin. They carry oxygen from the lungs to tissues and organs throughout the body, supporting cellular respiration and energy production.
- The absence of a nucleus and their biconcave shape enhance their flexibility for passage through narrow capillaries.