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Question #47408
The Question
Following the accidental removal of the parathyroid glands during a thyroidectomy, a patient exhibits a severe hormonal imbalance. Which of the following correctly identifies the primary resulting disorder and its precise physiological mechanism?
Options
- A.
Osteoporosis; decreased PTH levels prevent calcium deposition into the bone matrix, leading to decreased bone mass and fractures.
- B.
Tetany; hyposecretion of PTH causes systemic hypocalcemia, which lowers the threshold potential of neurons and triggers rapid muscle spasms.
- C.
Tetany; the absence of PTH leads to uninhibited calcitonin activity, causing systemic hypercalcemia and sustained muscle contraction.
- D.
Myasthenia gravis; low extracellular calcium inhibits the exocytosis of acetylcholine at the neuromuscular junction, causing muscle fatigue.
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
PTH|Calcitonin|Calcium_Channels|Osteoclasts
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in distinguishing between chronic structural bone disorders and acute neuromuscular irritability.
Students often falsely assume PTH 'builds' bone and link its deficiency to Osteoporosis.
In reality, PTH demineralizes bone to raise blood calcium.
Its absence causes acute hypocalcemia, which manifests electrochemically as Tetany (spasms) due to lowered neuronal threshold potentials, rather than structurally as Osteoporosis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Osteoporosis vs. Arthritis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |