Baroreceptors contribute to short-term regulation of arterial pressure by initiating reflex changes in heart rate and vascular tone. In which locations are the principal baroreceptors found?

Baroreceptors contribute to short-term regulation of arterial pressure by initiating reflex changes in heart rate and vascular tone. In which locations are the principal baroreceptors found?

• A. Coronary arteries
• B. Pulmonary arteries
• C. Carotid sinus and aortic arch in arterial walls
• D. Cerebral arteries

Answer: (C)

Baroreceptors are stretch-sensitive sensors that monitor the pressure inside arteries and trigger rapid reflexes to keep blood pressure within a normal range. The main ones are located in the carotid sinus, at the point where the common carotid splits, and in the aortic arch. When arterial pressure rises, these receptors increase their firing rate, signaling the brainstem to boost parasympathetic activity and reduce sympathetic activity. This slows the heart rate and causes some dilation of the vessels, helping to lower the pressure quickly. When pressure falls, firing decreases, leading the brainstem to raise sympathetic output and reduce parasympathetic activity, which speeds the heart and constricts vessels to raise the pressure. The other sites listed are not the principal baroreceptors responsible for this rapid short-term regulation.

Baroreceptors are stretch-sensitive sensors that monitor the pressure inside arteries and trigger rapid reflexes to keep blood pressure within a normal range. The main ones are located in the carotid sinus, at the point where the common carotid splits, and in the aortic arch. When arterial pressure rises, these receptors increase their firing rate, signaling the brainstem to boost parasympathetic activity and reduce sympathetic activity. This slows the heart rate and causes some dilation of the vessels, helping to lower the pressure quickly. When pressure falls, firing decreases, leading the brainstem to raise sympathetic output and reduce parasympathetic activity, which speeds the heart and constricts vessels to raise the pressure. The other sites listed are not the principal baroreceptors responsible for this rapid short-term regulation.