Q.40 Given below are two statements:
Statement I: Spleen participates in the immune response against blood-borne pathogens.
Statement II: The lymph node is a highly specialized primary lymphoid organ.
In the light of the above statements, choose the
correct answer from the options given below:
- Both Statement I and Statement II are true
- Both Statement I and Statement II are false
- Statement I is true but Statement II is false
- Statement I is false but Statement II is true
Spleen filters blood-borne pathogens as secondary lymphoid organ; lymph nodes are secondary, not primary.
Statement I correctly describes spleen’s immune role, while Statement II misclassifies lymph nodes as primary lymphoid organs (thymus/bone marrow are primary).
Question Breakdown
Statement I is true: spleen’s white pulp (B/T cell zones) and marginal zone macrophages filter blood pathogens, initiating adaptive immunity against bacteria/viruses. Statement II is false: lymph nodes are secondary lymphoid organs for antigen-specific responses; primary organs (thymus, bone marrow) handle lymphocyte maturation.
Option Analysis
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Both true: Incorrect. II wrong classification.
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Both false: Wrong. I accurate.
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Statement I true, Statement II false: Correct answer.
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Statement I false, Statement II true: False. Spleen essential for blood immunity.
Correct Answer
Statement I is true but Statement II is false.
Lymphoid Organs Classification
Primary lymphoid organs (bone marrow, thymus) produce/mature lymphocytes. Secondary lymphoid organs (spleen, lymph nodes, MALT) host immune responses. Spleen participates in the immune response against blood-borne pathogens via white pulp (PALS, follicles) and red pulp filtration.
Statement I: Spleen Function
Spleen filters 5% cardiac output daily, trapping encapsulated bacteria (pneumococcus) via marginal zone B cells and metallophilic macrophages. Splenectomy increases sepsis risk, proving its blood immunity role.
Statement II: Lymph Node Misclassification
Lymph node is a highly specialized primary lymphoid organ? False. Lymph nodes filter lymph (not blood), mature naive lymphocytes into effectors via HEVs and cortical sinuses. Primary = maturation sites only.
Organ Type Function Filters Bone marrow Primary B cell maturation Blood Thymus Primary T cell maturation Blood Spleen Secondary Blood pathogens Blood Lymph node Secondary Lymph antigens Lymph Exam Strategy
NEET/GATE trap: “Primary = produce/mature; Secondary = activate.” Spleen = blood filter (Statement I); lymph nodes = lymph filter (Statement II false). Mnemonic: “Primary Makes, Secondary Wakes”.
Perfect immunology classification question for your life sciences prep.
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