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Question #46198
The Question
In an experimental mammal, a targeted lesion in the hypothalamus disrupts the thermoregulatory feedback loop, preventing the integration of peripheral cold sensing with the TRH-TSH axis and sympathetic outflow. If this mammal is subsequently exposed to acute cold stress (), which of the following represents the most accurate physiological outcome?
Options
- A.
Complete abolition of compensatory thermogenesis, resulting in a decoupling of heat production from ambient sensing and a shift toward an ectothermic state of metabolic depression.
- B.
Autonomous activation of somatic motor neurons to initiate shivering, successfully compensating for the loss of non-shivering thermogenesis.
- C.
Compensatory hypersecretion of thyroxine () by the thyroid gland independent of the hypothalamic-pituitary axis to maintain the basal metabolic rate.
- D.
Sustained maintenance of core body temperature solely through local, autonomous peripheral vasoconstriction reflexes in the skin.
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
Hypothalamus|Negative Feedback|Set-point deviation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often harbor the misconception that endothermy (warm-bloodedness) is an intrinsic, autonomous property of all mammalian cells.
This question tests the understanding that endothermy is strictly dependent on a centralized neural feedback loop (the hypothalamic thermostat).
Failing to distinguish between local tissue reflexes and centrally coordinated systemic responses leads to selecting distractors involving 'autonomous' compensation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Thermoregulation logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |