Read the following passage and answer the question :
The primary lymphoid organs are bone marrow and thymus, where immature lymphocytes differentiate into antigen sensitive lymphocytes. They migrate to secondary lymphoid organ like spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix. All blood cells including lymphocytes are produced in bone marrow which is main lymphoid organ. Spleen is large reservoir of erythrocytes. It is large bean shaped organ mainly containing lymphocyte and phagocyte. It acts as filter of blood by trapping blood borne micro organism. Lymph nodes are small solid structures located at different points along lymphatic system. Antigens trapped in lymph node are responsible for activation of lymphocytes present there and cause the immune response. There is lymphoid tissue located within. Lining of major tracts like respiratory, digestive and urogenital tracts called mucous associated lymphoid tissue (MALT).
Which of the following is not feature of spleen?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → It shows reduction in size from birth to puberty.
Option (1) It is large reservoir of erythrocyte. — A feature of the spleen. The spleen stores a large number of red blood cells.
Option (2) It acts as filter of blood. — A feature of the spleen. The spleen acts as a filter of the blood: it traps micro-organisms carried in the blood. As a secondary lymphoid organ, it is a place where lymphocytes meet such antigens.
Option (3) It shows reduction in size from birth to puberty. — Not a feature of the spleen. This is a feature of the thymus, which is large at birth and shrinks to a very small size by puberty.
Option (4) It is a bean shaped organ containing Lymphocyte and Phagocyte. — A feature of the spleen. It is a large bean-shaped organ containing mainly lymphocytes and phagocytes.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Immune System in the Body – “… The bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced. The thymus is a lobed organ located near the heart and beneath the breastbone. The thymus is quite large at the time of birth but keeps reducing in size with age and by the time puberty is attained it reduces to a very small size.”