Topics:
Animal Physiology, Animal Refresher
Examples of Primary Lymphoid Organs
Which of the following is an example of primary lymphoid organs?
- All the above — Correct Answer
- Bone marrow only
- Thymus only
- Bursa of Fabricius only
Explanation:
Correct Answer: All the above
Primary lymphoid organs are the sites where lymphocytes originate and undergo maturation from stem cells (lymphopoiesis). All three are primary lymphoid organs:
Primary vs Secondary Lymphoid Organs
| Type | Examples | Function |
|---|---|---|
| Primary lymphoid organs | Bone marrow, Thymus, Bursa of Fabricius (in birds) | Site of lymphocyte production and maturation from stem cells |
| Secondary lymphoid organs | Spleen, Lymph nodes, Tonsils & adenoids, Peyer's patches, Appendix | Sites where mature lymphocytes encounter antigens and mount immune responses |
Key Details
- Bone marrow: Site of origin and maturation of B-lymphocytes in mammals; origin of all blood cells.
- Thymus: Site of maturation of T-lymphocytes; most active in young animals; involutes with age.
- Bursa of Fabricius: Unique to birds (found near the cloaca); equivalent to bone marrow in mammals for B-cell maturation; named after Hieronymus Fabricius.
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
