- 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 movements, sweating, salivation, etc. The autonomic system is subdivided into sympathetic and parasympathetic nervous systems. Sympathetic nerves lead from the middle section of the spinal cord and parasympathetic nerves from the brain and lower spinal cord. The heart, smooth muscles, and most glands receive fibres of both kinds: the interplay of sympathetic and parasympathetic reflex activity (the actions are often antagonistic) governs their working. For example, the parasympathetic system is responsible for slowing the heart rate and constricting the pupillary muscles; the sympathetic system increases the heart rate and dilates the pupil. Sympathetic nerve endings liberate noradrenaline as a neurotransmitter; parasympathetic nerve endings release acetylcholine.
The new mediacal dictionary. 2014.
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 — 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 … Universalium
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 — 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