Question

Bursa equivalent organ in human being regarding lymphocytes, is -

• A. Thymus
• B. Spleen
• C. Payer's patches
• D. Bone marrow

Hint:

To remember:
- "B" cells mature in the Bone marrow of mammals, which is equivalent to the Bursa of birds.
- "T" cells mature in the Thymus.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
B-lymphocytes (B cells) require specialized primary lymphoid microenvironments to undergo gene rearrangement, selection, and functional maturation.

Step 2: Detailed Explanation:
1. In avian species (birds), B-lymphocytes mature within a specialized primary lymphoid organ called the Bursa of Fabricius.
2. In mammals, including humans, there is no physical Bursa of Fabricius.
3. Instead, the bone marrow serves as the primary site of hematopoiesis, B-cell lineage commitment, and maturation.
Thus, the bone marrow is the functional mammalian equivalent of the avian bursa.
The thymus is the site of T-lymphocyte maturation, while the spleen and Peyer's patches are secondary lymphoid organs.

Step 3: Final Answer:
The correct option is 4, which corresponds to Bone marrow.