Most of the major muscle groups used or movement and communication are voluntary. Involuntary muscles would be things like your heart and the muscles around your intestines, which you generally cannot consciously control. The skeletal is called voluntary muscle because it is usually subject to conscious control.
Medical Definition of Autonomic nervous system. Autonomic nervous system: A part of the nervous system that regulates key involuntary functions of the body, including the activity of the heart muscle; the smooth muscles, including the muscles of the intestinal tract; and the glands.
By Kendra Cherry. Definition: The autonomic system is the part of the peripheral nervous system that is responsible for regulating involuntary body functions, such as heartbeat, blood flow, breathing and digestion. This system is further divided into two branches: the sympathetic system and the parasympathetic system.