autonomic nervous system
- the system of nerves and ganglia that innervates the blood vessels, heart, smooth muscles, viscera, and glands and controls their involuntary functions, consisting of sympathetic and parasympathetic portions.[1895-1900]
* * *Part of the nervous system that is not under conscious control and that regulates the internal organs.It includes the sympathetic, parasympathetic, and enteric nervous systems. The first, which connects the internal organs to the brain via spinal nerves, responds to stress by increasing heart rate and blood flow to the muscles and decreasing blood flow to the skin. The second comprises the cranial nerves and the lower spinal nerves, which increase digestive secretions and slow the heartbeat. Both have sensory fibres that send feedback on the condition of internal organs to the central nervous system, information that helps maintain homeostasis. The third division, embedded in the walls of the stomach and intestines, controls digestive movement and secretions.
* * *in vertebrates (vertebrate), the part of the nervous system that controls and regulates the internal organs without any conscious recognition or effort by the organism. The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The sympathetic nervous system connects the internal organs to the brain by spinal nerves. When stimulated, these nerves prepare the organism for stress by increasing the heart rate, increasing blood flow to the muscles, and decreasing blood flow to the skin. The nerve fibres of the parasympathetic nervous system are the cranial nerves (cranial nerve), primarily the vagus nerve, and the lumbar spinal nerves. When stimulated, these nerves increase digestive secretions and reduce the heartbeat.
* * *
Look at other dictionaries:
Autonomic nervous system — The autonomic nervous system Blue = parasympathetic Red = sympathetic Latin divisio autonomica systematis nervosi peripherici The autonomic nervous system (ANS or visceral nervous syste … Wikipedia
autonomic nervous system — n. the part of the nervous system that is responsible for control and regulation of the involuntary bodily functions, including those of the heart, blood vessels, visceral smooth muscles, and glands: it consists of the sympathetic system which,… … English World dictionary
Autonomic nervous system — Part of the nervous system that was once thought to be functionally independent of the brain. The autonomic nervous system regulates key functions of the body including the activity of the heart muscle (see below), the smooth muscles (e.g., the… … Medical dictionary
autonomic nervous system — ANS. The part of the nervous system that controls muscles of internal organs (such as the heart, blood vessels, lungs, stomach, and intestines) and glands (such as salivary glands and sweat glands). One part of the autonomic nervous system helps… … English dictionary of cancer terms
autonomic nervous system — noun the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands • Syn: ↑ANS • Hypernyms: ↑neural structure • Part Holonyms: ↑nervous system, ↑systema nervosum … Useful english dictionary
autonomic nervous system — the part of the peripheral nervous system responsible for the control of involuntary muscles (e.g. the heart, bladder, bowels) and hence those bodily functions that are not consciously directed, including regular beating of the heart, intestinal… … Medical dictionary
autonomic nervous system — the part of the peripheral nervous system responsible for the control of involuntary muscles (e.g. the heart, bladder, bowels) and hence those bodily functions that are not consciously directed, including regular beating of the heart, intestinal… … The new mediacal dictionary
autonomic nervous system — noun Date: 1898 a part of the vertebrate nervous system that innervates smooth and cardiac muscle and glandular tissues and governs involuntary actions (as secretion and peristalsis) and that consists of the sympathetic nervous system and the… … New Collegiate Dictionary
autonomic nervous system — noun 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… … Wiktionary
autonomic nervous system — noun Physiology, Anatomy the part of the peripheral nervous system which controls the involuntary functions of the glands, blood vessels, the viscera, and the heart and smooth muscles. Compare somatic nervous system … Australian English dictionary