Part of the nervous system which regulates the bodily functions that are not under conscious control: these include the heartbeat, intestinal movements, salivation, sweating, etc. The autonomic nervous system consists of two main divisions – the SYMPATHETIC NERVOUS SYSTEM and the PARASYMPATHETIC NERVOUS SYSTEM. The smooth muscles, heart and most glands are connected to nerve fibres from both systems and their proper functioning depends on the balance between these two. (See NERVES; NERVOUS SYSTEM.)