What do baroreceptors respond to when monitoring blood pressure?

Baroreceptors are specialized sensory receptors located mainly in the walls of the arteries, particularly in the carotid sinus and aortic arch. Their primary function is to detect changes in blood pressure by monitoring the degree of stretch in the arterial walls. When blood pressure increases, the arteries expand, and this stretch activates the baroreceptors. Conversely, if blood pressure decreases, the arteries become less stretched, and the activity of the baroreceptors diminishes.

This stretch-response mechanism is critical for the rapid regulation of blood pressure. When baroreceptors detect changes in arterial stretch, they send signals to the central nervous system, which then adjusts heart rate, vascular resistance, and other factors to maintain stable blood pressure levels.

While changes in blood volume, blood pH levels, and alterations in velocity of blood flow are important physiological parameters, they are not the primary stimuli for baroreceptor activity. Baroreceptors specifically respond to the mechanical changes in the arterial walls caused by variations in blood pressure.