autonomic nervous system. The division of the nervous system that regulates involuntary functions; innervates endocrine glands, smooth muscle, and heart muscle; and initiates the physiological changes that are part of the expression of emotion. See sympathetic and parasympathetic nervous systems.
autonomic nervous system. A major component of the peripheral nervous system, which regulates the body's internal environment by stimulating glands and by maintaining internal organs such as the heart, gall bladder, and stomach. go to glossary index
autonomic nervous system. controls the activities of organs, glands, and various involuntary muscles.