Parasympathetic Nervous System

A subdivision of the autonomic nervous system regulating largely involuntary internal processes, focused on energy storage, growth, and restoration (slows heart beat, stimulate digestion). Inhibits and opposes the sympathetic nervous system subdivision. See also freeze response, rest and digest and polyvagal theory.

Reference:

Bear, M.F., Connors, B.W. & Paradiso, M.A. (2001). Neuroscience: Exploring the Brain. (2nd Edition). Baltimore, MD: Lippincott Williams & Wilkins.