The primary control center for blood pressure is in the medulla oblongata of the brain. The homeostatic response to changes in blood pressure is the baroreceptor reflex. Baroreceptors in the carotid sinus and aortic arch sense stretch in the blood vessel walls due to pressure. The baroreceptors send signals to the medulla oblongata that control blood pressure.
The cardiovascular regulatory center in the medulla oblongata responds to changes in blood pressure. With decreased blood pressure, it begins a sympathetic response. Cardiac output is increased and the diameter of peripheral arterioles is decreased (vasoconstriction). Both of these work together to increase blood pressure. If blood pressure increases and become too high, a parasympathetic response through the vagus decreases heart rate and sympathetic tone in the arterioles is reduced, causing vasodilation. Together, these responses reduce blood pressure back into it normal range.
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