The autonomic nervous system ans is the part of the nervous system that regulates involuntary functions 1 examples are the heartbeat the digestive functions of the intestines control of respiration and secretion by glands basic anatomy and physiology. The autonomic nervous system the peripheral nervous system consists of the somatic nervous system sns and the autonomic nervous system ans the sns consists of motor neurons that stimulate skeletal muscles in contrast the ans consists of motor neurons that control smooth muscles cardiac muscles and glands. The autonomic nervous system controls cardiac and smooth muscle as well as glandular tissue the somatic nervous system is associated with voluntary responses though many can happen without conscious awareness like breathing and the autonomic nervous system is associated with involuntary responses such as those related to homeostasis. Full text full text is available as a scanned copy of the original print version get a printable copy pdf file of the complete article 158k or click on a page image below to browse page by page