a response controlled by the autonomic nervous system that changes the diameter of the arterioles. Since arterioles control the flow of blood from the arteries to the capillaries, smooth muscles in the walls of the arterioles conduct impulses and may react to anger, fear, or other emotions by producing dramatic changes of blood pressure.

ARTERIOLE REACTION: "A person's blood pressure drastically increased due to the changing of the diameter of arterioles, caused by an arteriole reaction."