Which brain region primarily controls sympathetic outflow to blood vessels?

• A. Cerebral cortex
• B. Hypothalamus
• C. Vasomotor center
• D. Cerebellum

Answer: (C)

The main concept here is how the autonomic nervous system sets the baseline tone of our blood vessels. The vasomotor center, located in the medulla oblongata of the brainstem, is the primary source of sympathetic outflow to the vessels. It integrates signals from baroreceptors and chemoreceptors and adjusts sympathetic nerve activity to the arterioles, producing vasoconstriction or relative vasodilation as needed to help maintain blood pressure and blood flow.

The cerebral cortex and cerebellum aren’t directly responsible for setting this vascular tone; they’re higher-level or motor centers. The hypothalamus does influence autonomic responses and can modulate how the brainstem centers respond, but the direct command to blood vessels comes from the vasomotor center. So, the vasomotor center is the correct focus for controlling sympathetic outflow to blood vessels.