Read the following passage carefully and answer the given questions.
The B-lymphocytes produce an army of proteins in response to pathogens. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Lymphoid organs are the organs where origin and/or maturation and proliferation of lymphocytes occur. The primary lymphoid organs are bone marrow and thymus. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix. Heroin commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum.
Which one of the following organs is not a secondary lymphoid organ in humans?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Parotid gland
Lymphoid organs are the organs where lymphocytes arise, mature and multiply. The primary lymphoid organs are the bone marrow and thymus, where lymphocytes are formed and mature. The passage says that mature lymphocytes then move to the secondary lymphoid organs: spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix. There the lymphocytes meet antigens and multiply.
Option (1) Spleen — A secondary lymphoid organ. The spleen has many lymphocytes and phagocytes, and filters the blood, catching microbes carried in the blood.
Option (2) Tonsils — A secondary lymphoid organ. The tonsils are lymphoid tissue in the throat that guards against microbes entering by the mouth.
Option (3) Parotid gland — Not a secondary lymphoid organ. The parotid gland is a salivary gland, part of the digestive system. It makes saliva, not lymphocytes.
Option (4) Peyer’s patches — A secondary lymphoid organ. These patches of lymphoid tissue lie in the lining of the small intestine; they belong to the MALT (mucosa associated lymphoid tissue).
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.