Baroreceptors monitor which aspect of the arterial wall to regulate blood pressure?

Baroreceptors monitor which aspect of the arterial wall to regulate blood pressure?

• A. Degree of stretch of the arterial wall
• B. Blood viscosity
• C. Temperature
• D. Oxygen content

Answer: (A)

Baroreceptors are stretch receptors in the walls of the carotid sinus and aortic arch. They detect changes in arterial pressure by sensing the degree of stretch of the arterial wall (transmural pressure). When blood pressure rises, more stretch increases their firing rate, signaling the brain to reduce heart rate and dilate vessels, which lowers BP. Conversely, when BP falls, less stretch decreases firing, triggering sympathetic activation to raise BP. The other factors listed—blood viscosity, temperature, and oxygen content—are monitored by different receptors (chemoreceptors for O2/CO2 and pH, thermoreceptors for temperature), not by baroreceptors.

Baroreceptors are stretch receptors in the walls of the carotid sinus and aortic arch. They detect changes in arterial pressure by sensing the degree of stretch of the arterial wall (transmural pressure). When blood pressure rises, more stretch increases their firing rate, signaling the brain to reduce heart rate and dilate vessels, which lowers BP. Conversely, when BP falls, less stretch decreases firing, triggering sympathetic activation to raise BP. The other factors listed—blood viscosity, temperature, and oxygen content—are monitored by different receptors (chemoreceptors for O2/CO2 and pH, thermoreceptors for temperature), not by baroreceptors.