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Question #46326
The Question
A mammalian species adapted to a sub-zero habitat exhibits morphological traits consistent with Allen's Rule. During acute cold stress, it sustains thermal homeostasis via increased endogenous thermogenesis. Which of the following accurately describes the consequent integration of its metabolic flux and neural respiratory feedback loop?
Options
- A.
The elevated metabolic flux increases pCO2 and H+ production, which strongly activates the chemosensitive area adjacent to the medullary rhythm centre, shifting the respiratory set-point higher.
- B.
The heightened oxygen demand for thermogenesis directly stimulates the carotid and aortic bodies, which signal the pneumotaxic centre to increase the duration of inspiration.
- C.
The minimized surface-to-volume ratio inherently lowers the basal metabolic rate, thereby decreasing the pCO2 stimulus to the central chemoreceptors.
- D.
The cold stress directly stimulates the stretch receptors in the lungs, triggering the Hering-Breuer reflex to hyperventilate and clear excess metabolic heat.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Allen’s_Rule_and_Surface-to-Volume_Ratio|Neural_Regulation_Feedback|Metabolic_Flux_and_Steady_State
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating morphological adaptations (Allen's Rule) with physiological feedback loops (Respiratory Regulation).
The primary trap is the 'Oxygen Misconception'—students intuitively think high metabolic demand drives respiration via oxygen depletion, but NCERT strictly dictates that pCO2 and H+ are the primary drivers for the medullary chemosensitive area.
A secondary trap tests the exact function of the pneumotaxic centre (which limits inspiration duration).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Breathing and Exchange of Gases - Class 11 |
| Concept | Neural Regulation Feedback |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |