The autonomic system consists of the heart, blood vessels, guts, lungs etc., it's those organs not under strict voluntary control. It is modulated however, by the central nervous system's
sympathetic and parasympathetic nervous systems.
Autonomic Nervous System
The autonomic nervous system regulates the autonomic system. It is divided into two main branches… the
parasympathetic nervous system drives an animal towards R & R, promoting digestion, slowing the heart etc., whilst the sympathetic nervous system is responsible for the fight or flight response.