Final answer:
The higher brain centers responsible for increasing cardiac output and resistance in response to anxiety or stress are primarily located in the medulla of the brain. Specifically, the cardiovascular center within the medulla controls the smooth and cardiac muscles of the cardiovascular system through autonomic connections.
Step-by-step explanation:
The higher brain centers responsible for increasing cardiac output and resistance in response to anxiety or stress are primarily located in the medulla of the brain. Specifically, the cardiovascular center within the medulla controls the smooth and cardiac muscles of the cardiovascular system through autonomic connections.
When descending inputs from the hypothalamus stimulate this area, the sympathetic system can increase activity in the cardiovascular system. This results in an increase in heart rate and blood pressure, as well as vasoconstriction. These responses help prepare the body to deal with a dangerous situation.