Blood pressure regulation reflex includes pressor reflex and decompression reflex, due to the existence of pressure receptors in the carotid sinus and the aortic arch, when the blood pressure rises for some reason, the pressure receptors issue more impulses to the center, which can make the cardiac inhibitory center excitability enhancement, cardiac accelerating center excitability weakening, vasoconstrictor center excitability decrease, thus causing the heart rate to slow down, the cardiac output decreases, and peripheral vasodilatation makes the blood pressure fall. When the blood pressure falls for some reason, the impulse issued by the pressure receptors to the center decreases, thus increasing the excitability of the cardiac accelerating center, decreasing the excitability of the cardiac inhibiting center, and increasing the excitability of the vasoconstricting center, which causes the heart rate to increase, the cardiac output to increase, and the peripheral vascular resistance to increase so that the blood pressure rises.