Question

Function of human spleen
A. Control the pulse rate
B. Secrete hormone
C. Stimulate heart
D. Control blood volume

Answer 1

Hint: Immune system comprises lymphoid organs, tissues cells and soluble molecules like antibodies. This system is unique as it recognizes foreign bodies, responds to these antigens, and remembers them. Besides, it plays a role in allergic reactions, autoimmune diseases, and organ transplantation.

Complete step-by-step answer: The lymphoid organs are the sites where lymphocytes originate and or mature and proliferate. Lymphoid organs are categorized as primary lymphoid organs and secondary organs. These secondary lymphoid organs include the spleen, lymph nodes, tonsils, Peyer’s patches of the small intestine, and appendix. Secondary lymphoid organs are the sites for the interaction of lymphocytes with the antigen and consequently their proliferation to become effector cells. The spleen is a large bean-shaped organ having white pulp and red pulp. It mainly consists of lymphocytes, phagocytes and is also a reservoir of erythrocytes. The spleen acts as a filter of blood as it traps blood-borne microorganisms.
So the correct answer is option D, i.e., Control blood volume.
Additional information:
Lymph nodes: These are small, solid structures located at specific sites along with the lymphatic system. Antigens that happen to enter the lymph and tissue fluid activate the lymphocytes present in the lymph nodes leading to the immune response.
MALT: These comprise lymphoid tissues that are located within the lining of the respiratory tract, digestive tract, and urogenital tract.

Note: Primary lymphoid organs include bone marrow and thymus. In these organs, immature lymphocytes differentiate into antigen sensitive lymphocytes. After maturation, the lymphocytes migrate to secondary lymphoid organs.