In a patient with chronic established essential hypertension, the carotid sinus baroreceptors continue to fire normally at the elevated pressure. This observation is best explained by:

• A Permanent damage to glossopharyngeal afferents
• B Loss of baroreceptor function, so they fire randomly
• C Resetting of the baroreceptor firing threshold upward within days of sustained pressure elevation ✓
• D Conversion of baroreceptors into chemoreceptors under sustained stretch

Explanation

Baroreceptors adapt or reset when arterial pressure stays elevated for one to two days. Their stimulus response curve shifts toward the new higher pressure, so they again register changes around the hypertensive level rather than signalling constant hypotension. This is why baroreceptors buffer acute swings effectively but do not defend against chronic hypertension, and why long term control depends on renal fluid handling. They remain structurally intact and continue to modulate short term variability.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.