What is the role of baroreceptors?

• A. To detect changes in blood pressure
• B. To regulate breathing
• C. To control heart rate directly
• D. To sense blood glucose

Answer: (A)

Baroreceptors are stretch-sensitive sensors located in the carotid sinus and aortic arch that monitor arterial pressure by detecting how much the vessel walls are stretched. When blood pressure rises, they fire more rapidly and send signals to the brainstem, which lowers sympathetic activity and increases parasympathetic (vagal) activity. The result is a slower heart rate, less contractility, and some vasodilation, all of which help bring blood pressure down toward normal. When blood pressure falls, firing decreases, allowing increased sympathetic outflow and reduced parasympathetic influence, which raises heart rate, increases contractility, and causes vasoconstriction to raise the pressure again.

This reflex is a rapid, short-term mechanism to maintain stable blood pressure during changes in posture or activity. It doesn’t directly regulate breathing, and it isn’t a direct control of heart rate on its own; rather, it modulates heart rate and vascular tone through autonomic reflexes. It also has nothing to do with sensing blood glucose.