Which receptors respond to arterial wall stretch and detect changes in blood pressure?

• A. Baroreceptors
• B. Chemoreceptors
• C. Proprioceptors
• D. Adrenaline

Answer: (A)

Baroreceptors are mechanoreceptors in the carotid sinus and aortic arch that detect how much the arterial walls stretch as blood pressure changes. When blood pressure rises, they fire more rapidly and send signals to the brainstem, which triggers reflexes to lower heart rate and cause vasodilation, bringing BP back down. If BP falls, their firing decreases, leading to increased sympathetic activity that raises heart rate, contractility, and peripheral vasoconstriction to restore pressure.

Chemoreceptors monitor blood chemicals like O2, CO2, and pH; proprioceptors sense body position; adrenaline is a hormone that can raise BP but is not a receptor.