The sensory nerve cells in the aortic arch and carotid sinus are called high pressure baroreceptors. They regulate systemic blood pressure and cerebral blood pressure.
(i) Control of low blood pressure: When the blood pressure in the heart and blood vessels decreases, the baroreceptor signal level decreases. This message travels to the medulla oblongata via the glossopharyngeal and vagus nerves. Signals from the medulla oblongata are sent to the heart muscle, pressor, and blood vessels. It increases heart rate and constricts blood vessels. As a result, the blood pressure becomes normal.
(ii) Regulation of high blood pressure: When the blood pressure in the heart and blood vessels increases, the baroreceptor signal increases. This message passes through the medulla oblongata. It shuts down the vasomotor center. As a result, blood flow through the heart and blood vessels decreases. As a result, the blood pressure becomes normal.