Stimulation of the carotid sinus triggers which response?

• A. Bradycardia
• B. Tachycardia
• C. Hypertension
• D. No change

Answer: (A)

Stimulation of the carotid sinus engages baroreceptors that sense arterial pressure. When these receptors fire more due to increased stretch, the brainstem activates the baroreflex, boosting parasympathetic (vagal) output to the heart and reducing sympathetic activity. The net result is a slower heart rate, i.e., bradycardia, and often a drop in blood pressure. Choices suggesting tachycardia or hypertension reflect the opposite autonomic response, while no change would not fit a reflex designed to adjust flow in response to pressure. So the expected outcome is bradycardia.