autonomic nervous system science definition

The part of the vertebrate nervous system that regulates involuntary activity in the body by transmitting motor impulses to cardiac muscle, smooth muscle, and the glands. The muscular activity of the heart and of the circulatory, digestive, respiratory, and urogenital systems is controlled by the autonomic nervous system. The autonomic nervous system is divided into two parts: the sympathetic nervous system  and the parasympathetic nervous system .