Autonomic nervous system
The autonomic nervous system (ANS or visceral nervous system or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system that functions largely below the level of consciousness to control visceral functions, including heart rate, digestion, respiratory rate, salivation, perspiration, pupillary dilation, micturition (urination), sexual arousal, breathing and swallowing. Most autonomous functions are involuntary but they can often work in conjunction with the somatic nervous system which provides voluntary control.
The sympathetic nervous system is one of the two main divisions of the autonomic nervous system, the other being the parasympathetic nervous system.
Dysautonomia (or autonomic dysfunction, autonomic neuropathy) is an umbrella term for various conditions in which the autonomic nervous system (ANS) does not work correctly.