Baroreceptors are receptors sensitive to changes in what parameter?

• A. Temperature
• B. Light
• C. pH
• D. Blood pressure

Answer: (D)

Baroreceptors are stretch‑sensitive receptors that monitor blood pressure by detecting the stretch of arterial walls, primarily in the carotid sinus and aortic arch. When blood pressure increases, they fire more rapidly, signaling the brainstem to lower BP through reduced heart rate and contractility and by promoting vasodilation. When BP drops, firing decreases, triggering sympathetic outflow to raise heart rate, increase contractility, and cause vasoconstriction to bring BP back up. This rapid reflex helps stabilize blood pressure during changes in posture or activity. Other options don’t fit because temperature and light are detected by thermoreceptors and photoreceptors, respectively, and pH is monitored by chemoreceptors that influence respiration and circulatory adjustments rather than the baroreceptor reflex.