Question

Which is not an example of secondary lymphoid organ

• A. Appendix
• B. Thymus gland
• C. Tonsils
• D. Peyer's patches of small intestine

Answer 1

Answer: (B)

Thymus gland

• Lymphoid organs are of two types. They are primary lymphoid organs and secondary lymphoid organs.
• Primary lymphoid organs are the lymphoid organs in which lymphocytes are produced and undergo development and are then supplied to secondary lymphoid organs. For example, Bone marrow and thymus gland.
• Secondary lymphoid organs are the lymphoid organs in which lymphocytes are activated to participate in the specific immune response. For example, Appendix, Tonsils, spleen, Peyer's patches of the small intestine, etc.
• Hence Thymus gland is not an example of the secondary lymphoid organ.
• So, the correct answer is 'Thymus gland'.