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Question #46931
The Question
A patient mistakenly receives an ABO-incompatible blood transfusion, triggering a massive immune response. Shortly after, the patient exhibits a paradoxical clinical picture: widespread micro-clots in intact blood vessels followed by severe, uncontrollable hemorrhage. Which of the following physiological sequences best explains the onset of this hemorrhagic phase?
Options
- A.
Massive IgM-mediated hemolysis releases pro-coagulant substances that systemically activate the clotting cascade, leading to the exhaustion of fibrinogen, prothrombin, and platelets.
- B.
Donor antibodies directly neutralize the recipient's thrombokinase, blocking the conversion of prothrombin to thrombin and inducing systemic hemorrhage.
- C.
Activated complement proteins competitively bind to the active site of thrombin, preventing the conversion of soluble fibrinogen into insoluble fibrin threads.
- D.
The massive formation of antigen-antibody complexes precipitates serum calcium ions (Ca2+), which are essential for the activation of both intrinsic and extrinsic coagulation pathways.
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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
Clotting Cascade Factors|ABO-Rh Incompatibility Logic|Key Analytical Nature
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often view immunity (Human Health and Disease) and coagulation (Body Fluids and Circulation) as isolated systems.
The core trap is 'consumptive coagulopathy'—the counterintuitive concept that massive over-activation of the clotting cascade directly causes severe bleeding due to the exhaustion of clotting factors.
Distractors exploit common half-truths, such as the role of calcium in clotting or the inhibitory actions of antibodies, to test if the student understands the exact mechanism of cross-system pathophysiology.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | The Living World - Class 11 |
| Concept | Key Analytical Nature |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |