Written by the Fiveable Content Team โข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated September 2025
Definition
The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.
This is one half of the autonomic nervous system; it prepares the body for intense physical activity and is often referred to as the fight-or-flight response.
This is another half of the autonomic nervous system; it relaxes the body and inhibits or slows many high energy functions - often referred to as rest-and-digest or feed-and-breed activities.