Depressor Reflexes

the decrease in arterial pressure and the deceleration of heartbeat that result upon stimulation of the vascular reflexogenic zones, which are located mainly in the aortic arch and in the branches of the trunks of the common carotid arteries. When there is increased blood pressure in these zones or dilatation of the walls of the heart, there is an onset of excitation of special sensory nerve endings (dilatation receptors). The impulses that arise in these receptors excite the vagus nerve centers in the medulla oblongata and relax the tonus of the vasomotor center, which leads to a decrease in arterial pressure and heart rhythm. The depressor reflexes are part of the system of autoregulatory mechanisms, which maintain arterial pressure and heart rhythm at the proper level for a given species.