arteriole /ärtir″ē·ōl/ [L, little artery] , the smallest of the arteries. Blood flowing from the heart is pumped through the arteries, to the arterioles, to the capillaries, into the veins, and returned to the heart. The muscular walls of the arterioles constrict and dilate in response to both local factors and neurochemical stimuli; thus, arterioles play a significant role in peripheral vascular resistance and in regulation of blood pressure. Also called arteriola. See also artery.
