Which of the following is a secondary lymphoid organ?
(a) Brunner's gland
(b) Peyer's patches
(c) Crypts of Leiberkuhin
(d) Glisson's capsule

Options

A. Brunner's gland
B. Peyer's patches
C. Crypts of Leiberkuhin
D. Glisson's capsule

Answer

To solve the question, "Which of the following is a secondary lymphoid organ?", we will analyze each option provided:

1. **Understanding Lymphoid Organs**:
- Lymphoid organs are classified into two main categories: primary and secondary lymphoid organs.
- Primary lymphoid organs are involved in the production and maturation of lymphocytes (B and T cells). The primary lymphoid organs include the thymus and bone marrow.
- Secondary lymphoid organs are where lymphocytes are activated and proliferate. These include lymph nodes, spleen, tonsils, and mucosa-associated lymphoid tissue (MALT), which includes Peyer's patches.

2. **Analyzing the Options**:
- **(a) Brunner's gland**: These are glands located in the submucosa of the duodenum and are involved in secreting alkaline mucus to neutralize stomach acid. They are not lymphoid organs.
- **(b) Peyer's patches**: These are clusters of lymphoid tissue found in the small intestine, specifically in the ileum. They are part of the MALT and are involved in the immune response, making them a secondary lymphoid organ.
- **(c) Crypts of Lieberkühn**: These are intestinal glands found in the lining of the small intestine and are involved in secretion and absorption. They are not lymphoid organs.
- **(d) Glisson's capsule**: This is a layer of connective tissue surrounding the liver. It is not a lymphoid organ.

3. **Conclusion**:
- Among the options provided, the only secondary lymphoid organ is **(b) Peyer's patches**.

Thus, the correct answer is **(b) Peyer's patches**.