State the location of the vasomotor center and name its two parts. Name the division of the autonomic nervous system that carries impulses to blood vessels. Which blood vessels? Which tissue in these vessels? Explain why normal vasoconstriction is important. Explain how greater vasoconstriction is brought about. Explain how vasodilation is brought about. How will each of these changes affect blood pressure? (pp. 313-314)

Answer: The vasomotor center, located in the medulla oblongata of the brainstem, regulates blood pressure by controlling the constriction and dilation of arterioles. It consists of two parts: the vasoconstrictor area and the vasodilator area. Increased vasoconstriction raises blood pressure by narrowing blood vessels, increasing resistance to blood flow, and forcing the heart to pump harder. On the other hand, vasodilation lowers blood pressure by widening blood vessels, reducing resistance to blood flow, and allowing blood to flow more easily, thus reducing the workload on the heart. The sympathetic division of the autonomic nervous system carries impulses to the blood vessels, primarily affecting smooth muscle tissue in arterioles.