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Question #45444

Difficulty: 8/10 | 🟢 Free

The Question

A synthetic analog of Parathyroid Hormone (PTH) is designed with a structural modification that significantly extends its plasma half-life. If administered chronically to a normal mammalian model, which of the following physiological outcomes will be observed?

Options

  • A.

    Sustained osteoclast activation leading to refractory hypercalcemia, overwhelming Thyrocalcitonin (TCT) and causing decreased neuromuscular excitability.

  • B.

    Enhanced osteoblast proliferation leading to bone hypercalcification, accompanied by tetanic muscle spasms.

  • C.

    Increased renal excretion of calcium and phosphate, leading to hypocalcemia and hyperphosphatemia.

  • D.

    Upregulation of Thyrocalcitonin (TCT) receptors on osteoclasts, resulting in a negative feedback loop that completely normalizes blood calcium levels.

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Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Comparative_Analysis

Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.

Concepts Behind This Question

PTH|Thyrocalcitonin|Hormone Half-life Logic

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Students frequently confuse the neuromuscular effects of calcium imbalances, associating all parathyroid disorders with 'Tetany' (which is strictly due to hypocalcemia/hypoparathyroidism).

This question requires synthesizing the hypercalcemic role of PTH, the concept of hormone half-life overriding negative feedback (TCT), and the physiological consequence of hypercalcemia (decreased neuromuscular excitability).

Quick Facts About This Question

Question Information

SubjectBiology
ChapterChemical Coordination and Integration - Class 11
ConceptInsulin vs Glucagon Effects
Difficulty8
Cognitive Load5
Target Solve Time120 sec
AccessFree