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Question #47451
The Question
Chronic psychological stress often leads to a hyperactive Hypothalamic-Pituitary-Adrenal (HPA) axis. In severe cases, patients may experience recurrent vertigo and a loss of postural equilibrium. Based on the physiological integration of the endocrine and sensory systems, which of the following mechanisms best explains this stress-induced vestibular impairment?
Options
- A.
Elevated cortisol levels bind to receptors in the inner ear, altering Na+/K+-ATPase activity and disrupting the K+-rich endolymph homeostasis.
- B.
Hypersecretion of ACTH directly degrades the calcium carbonate otoliths in the macula, impairing static equilibrium.
- C.
Excess glucocorticoids inhibit the mechanoreceptors in the Organ of Corti, preventing the generation of action potentials in the vestibular nerve.
- D.
Stress-induced epinephrine release causes severe vasoconstriction of the Eustachian tube, altering fluid pressure in the membranous labyrinth.
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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
Hypothalamic-Pituitary Axis Integration|Vestibular Equilibrium Mechanics
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often compartmentalize the endocrine and sensory systems.
This question tests the synthesis of NCERT concepts: recognizing that steroid hormones regulate ionic pumps (like Na+/K+-ATPase) which are critical for maintaining the specialized fluid (endolymph) of the inner ear.
It also relies on a classic Location/Functional Trap, requiring students to distinguish between the Organ of Corti (hearing) and the vestibular apparatus (balance), as well as the middle ear (Eustachian tube) versus the inner ear.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Vestibular Equilibrium Mechanics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |