Question

Life span of mammalian R.B.C. is
a. 120-128 days
b. 100 days
c. Less than 100 days
d. None of the above

Answer 1

Hint: The full form of RBC is red blood cells, they are also called erythrocytes, where the principle function of the erythrocytes is to carry oxygen to all body parts by hemoglobin present in its cytoplasm. And this is the chief cells present in the circulatory system, and they are very large in number.

Complete answer:
- The red blood cells chief function is to transport, in mammals, including humans, the shape of RBC are biconcave disc shape, they are flattened at the center and they are dumbbell-shaped in cross-section.
- The diameter 6 to 6.5 micrometers, and when coming to thickness it is 2 to 2.5 micrometers, and least thickness at the center and maximum thickness at the periphery.
- Humans have 4 to 5 millions of blood per microliter of the blood.
- Red blood cells are formed from the bone marrow by a process called erythropoiesis, and it takes 7 days for the cells to develop from immature cell to mature blood cells
- At an early age, human RBC has a nucleus, but at the time of maturation, the nucleus disintegrates.
- Once red blood cells mature the average life span in adults is in the range of 100 to 120 days.
- Later they disintegrated or destroyed the spleen.

Hence, the correct answer is option (A).

Note: When the red blood cells become aging some changes occur in the structure such as plasma membrane and all, so the cells such as macrophages and phagocytes recognize those cells, and undergo phagocytosis, and the process of programmed cell death occurs called eryptosis.