The autonomic nervous system is comparable to the autopilot in an airplane. This is because the autonomic nervous system does not need conscious input for it to work and functions autonomically. The autonomic nervous system is comprised of the symphatetic nervous system, parasymphatetic nervous system, and the enteric nervous system. The symphatetic nervous system regulates the “fight or flight” response by doing actions such as pupilary dilatation, sweating, etc. The parasyphatetic nervous system regulates the “rest and digest” response by doing actions such as pupilary constriction, defecation, etc. The enteric nervous system is an autonomic nervous system solely for the gastrointestinal tract.
