autonomic nervous system

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The part of the vertebrate nervous system that regulates involuntary action, as of the intestines, heart, and glands, and that is divided into the sympathetic nervous system and the parasympathetic nervous system.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun neuroanatomy In humans and other vertebrates, the part of the nervous system that regulates the involuntary activity of the heart, intestines and glands. These activities include digestion, respiration, perspiration, metabolism, and the modulation of blood pressure.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands