Question

Spleen and thymus are hematopoietic for
(a) RBC
(b) WBC
(c) Platelets
(d) None of the above

Answer 1

Hint: Hematopoiesis refers to the production of blood cells. Blood cell formation takes place in the body in different organs of the body. Spleen and thymus are lymphoid organs of the body. The lymphoid system of the body is a part of the circulatory system and immune system and it is involved in the production of cells and also in the destruction of cells.

Complete answer:
 Spleen and thymus are hematopoietic for WBC. 20-30% of WBCs are formed in the lymphoid organs- spleen and thymus. WBCs are involved in immune responses of the body and as the spleen and thymus being the lymphoid organs are also responsible for immune responses of the body thus spleen and thymus are hematopoietic for WBCs.

Additional Information: - WBCs are of 5 different types- lymphocytes (they are immune cells of two types- B and T lymphocytes), monocytes (fights certain infections and helps with immunity also), neutrophils (involved in immunity), basophils( contains heparin, a natural blood-thinning substance, involved in allergic reactions) and eosinophils( functions in inflammatory responses).
- RBCs are destroyed in the spleen. They are produced in the bone marrow. In the fetus, RBCs are produced in the yolk sac first and then in the liver and then it moves to the bone marrow.
- Platelets are responsible to stop bleeding in case of an injury. They form clots and stop bleeding. They are formed from megakaryocytes by division.
RBC- RBC is formed in the bone marrow.
WBC- WBC is formed in the spleen and thymus
Platelets- Platelets are formed in the bone marrow.
So, the correct answer is `WBC`.

Note: Hematopoiesis is the process of the formation of blood cells in the body. Lymphoid organs are responsible for the immune responses of the body. RBCs have a lifespan of 120 days in the human body. WBCs have a lifespan of 13 days. Platelets have about 10 days of a life span. If there is a decrease in the count of RBC, WBC, or platelets this leads to an abnormal diseased condition.