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Question #46354
The Question
A patient with advanced metastatic bone cancer develops severe anemia. Laboratory investigations reveal abnormally high titers of erythropoietin (EPO) and an enlarged spleen. However, the peripheral blood reticulocyte count is nearly zero. Which of the following statements correctly identifies the primary pathophysiological mechanism and the reason for splenomegaly?
Options
- A.
Metastatic cells competitively bind to EPO receptors in the bone marrow; the spleen enlarges due to increased destruction of defective RBCs.
- B.
Physical displacement of hematopoietic niches by tumor cells renders EPO ineffective; the spleen enlarges due to compensatory extra-medullary hematopoiesis.
- C.
High EPO levels induce rapid apoptosis of erythroblasts in the marrow; the spleen enlarges to store the excess circulating iron.
- D.
The juxtaglomerular cells secrete a mutated, inactive form of EPO due to tumor-induced hypoxia; the spleen enlarges to synthesize functional EPO.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Bone_Marrow_Microenvironment|Malignancy|Erythropoietin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that high stimulating hormone levels (EPO) must always lead to high product levels (RBCs), or that a failure in production implies a lack of the hormone.
They must recognize that target tissue integrity (bone marrow niches) is an absolute prerequisite for hormonal action.
Furthermore, this tests the 'Functional Overlap' trap: students strictly memorize the spleen as the 'graveyard of RBCs' (NCERT fact) and may fail to recognize its compensatory role in extra-medullary hematopoiesis during severe marrow failure.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Body Fluids and Circulation - Class 11 |
| Concept | Erythrocyte Lifecycle and Location |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |