Question

Number of RBC in an adult man per mm${}^3$ of blood is

• A. 5,000
• B. 50,000
• C. 500,00
• D. 5,000,000

Answer 1

Answer: (D)

5,000,000

The RBC count is the total number of red blood cells per cubic millimeter of blood. In response to hypoxia, the hormone erythropoietin, secreted by the kidneys, stimulates the bone marrow to produce red blood cells. The formation of red blood cells is known as erythropoiesis. Normal red blood cells values at various ages are:

Newborns: 4.8 - 7.2 million,

Adults: (males): 4.6 - 6.0 million,

Females: 4.2 - 5.0 million,

Pregnancy: slightly lower than normal adult values and

Children: 3.8 – 5.5 million.

Thus, the correct answer is option D.