Autonomic nervous system (ANS)

The part of the nervous system that is concerned with control of involuntary body functions, such as glandular secretions, heart beat, bowel function, bronchodilation, bronchoconstriction, vasodilation, and vasoconstriction. Also called the visceral nervous system, as opposed to the somatic nervous system. The sympathetic and parasympathetic nervous systems are subdivisions of the autonomic nervous system.