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Abbreviation for autonomic nervous system.

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American Nimodipine Study. A clinical trial that assessed nimodipine’s effect on mortality in post-acute stroke patients.
Conclusions Nimodipine has no effect on patients at 48 hours, but may be beneficial at 18 hours.

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Abbreviation for autonomic nervous system.

autonomic nervous system

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AUTONOMIC NERVOUS SYSTEMThe parts of the nervous system that control unconscious, involuntary, and visceral body functions. The autonomic nervous system reflexively balances the body's smooth muscle tone, blood pressure, temperature, fluid composition, state of digestion, metabolic activity, and sexual activation. In the central nervous system (CNS), the activities of the autonomic nervous system (ANS) are coordinated in the brainstem (especially in the nucleus of the tractus solitarius) and in the hypothalamus. In the peripheral nervous system (PNS), the ANS comprises the visceral motor axons, the visceral sensory axons, and the enteric nervous system (a neural net within the walls of the gastrointestinal tract). Compared to peripheral somatic axons, the peripheral autonomic axons tend to be small (less than 3 µm in diameter), slowly conducting, and sparsely myelinated. The autonomic motor circuits also differ from somatic motor pathways. Peripheral somatic motor pathways, i.e., the circuitry sending signals to skeletal muscles, are only one axon long; axons of somatic motor neurons in the spinal cord and brainstem synapse directly on the effector cell, a muscle cell. In contrast, peripheral autonomic motor pathways are two axons long. First, an axon (a preganglionic axon) of a visceral motor neuron in the spinal cord or brainstem synapses on a neuron in a peripheral ganglion. Second, the axon (a postganglionic axon) of the ganglion neuron synapses on the effector cell, a smooth muscle cell, a cardiac muscle cell, or a secretory cell.

This autonomic motor circuitry is further subdivided into two parallel subsystems; the sympathetic and the parasympathetic. The subsystems differ in two major ways: 1. In the sympathetic system, the central (preganglionic) neurons are located only in the thoracic and lumbar segments of the spinal cord; in the parasympathetic system, the central neurons are located only in the brainstem and in a short segment of the caudal end of the spinal cord. 2. In the sympathetic system, norepinephrine is the characteristic neurotransmitter of the postganglionic axons; in the parasympathetic system, acetylcholine is the characteristic neurotransmitter of the postganglionic axons. In both the sympathetic and parasympathetic systems, the characteristic neurotransmitter of the preganglionic axons is acetylcholine.Besides their characteristic neurotransmitters, autonomic nerves influence surrounding tissues through the release of other active chemicals including ATP, nitric oxide, and a range of peptides, e.g., substance P and vasoactive intestinal peptide. As a result of their different final transmitters, the effects of the two subsystems differ. Sympathetic stimulation readies an animal for interaction with the outside world and prepares the animal for "fight or flight"; e.g., activation of sympathetic axons increases heart rate and decreases gastrointestinal peristalsis. On the other hand, parasympathetic stimulation relaxes and quiets an animal; e.g., activation of parasympathetic axons decreases heart rate and increases gastrointestinal peristalsis. The accompanying table compares the effects of sympathetic and parasympathetic stimulation on specific tissues. See: parasympathetic nervous system; sympathetic nervous system; illustrationtable

Pathology

The ANS is distributed throughout the body, and autonomic dysfunction can produce a wide range of symptoms, such as bladder malfunction, blood pressure abnormalities, breathing difficulty, gastrointestinal motility problems, heart arrhythmias, impotence, nasal congestion, sweating disorders, syncope, and visual symptoms. Drugs that act on or mimic autonomic neurotransmitters are commonly used to alleviate these symptoms as well as other conditions, such as glaucoma, heart failure, shock, and thyroid storm. To assess the overall functioning of the ANS, physicians often begin with simple measurements of the reflexive responses of the cardiovascular system; specifically, they measure the changes of blood pressure and heart rate as a person stands from sitting and exercises.

Tissue:	Effects:
	Sympathetic Stimulation	Parasympathetic Stimulation
adipose tissue	lipolysis
adrenal cortex
secretion (corticoids)	increase
adrenal medulla
secretion (adrenaline)	increase
arteries
abdominal organs	constriction
coronary	dilation
skin and mucosa	constriction
bladder
wall (detrusor) muscle	relaxation	contraction
sphincter	contraction	relaxation
gall bladder
wall muscle	relaxation	contraction
duct	dilation	constriction
heart
AV node (conduction velocity)	increase	decrease
SA node (rate)	increase	decrease
atrial muscle (contractility)	increase	decrease
ventricular muscle (contractility)	increase
intestine
wall muscle (tone and motility)	decrease	increase
secretion	decrease	increase
rectal sphincter muscle	contraction	relaxation
kidney
secretion (renin)	increase
lacrimal gland
secretion (tears)		increase
liver
metabolism	glycogenolysis, gluconeogenesis	glycogen synthesis
bile secretion	decrease	increase
lung
airways	dilation	constriction
secretion (airway glands)		increase
nasopharynx
secretion (mucosal glands)		increase
pancreas
secretion (enzymes and insulin)	decrease	increase
secretion (glucagon)	increase
pineal gland
melatonin synthesis	stimulation
pupil	dilation	constriction
reproductive tract
muscles	contractions
blood vessels	constriction	dilation, erection
salivary gland
secretion	decrease	increase
skeletal muscle	increase contractility, glycogenolysis
skin
pilomotor muscle	contraction
secretion (sweat)	increase
spleen
capsule	contraction
stomach
wall muscle (tone and motility)	decrease	increase
secretion	decrease	increase
uterus
pregnant	contraction
nonpregnant	relaxation

Autonomic nervous system (ANS)

The part of the nervous system that supplies nerve endings in the blood vessels, heart, intestines, glands, and smooth muscles, and governs their involuntary functioning. The autonomic nervous system is responsible for the biochemical changes involved in experiences of anxiety.Mentioned in: Anxiety

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Abbreviation for autonomic nervous system.

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Acronym	Definition
ANS➣Answer
ANS➣American Nuclear Society
ANS➣Advanced Networking Services
ANS➣Answer (logging abbreviation)
ANS➣American National Standard
ANS➣Aquatic Nuisance Species
ANS➣Autonomic Nervous System
ANS➣Ammonium Nitrate Solution
ANS➣Air Navigation Service
ANS➣American Numismatic Society
ANS➣Anna Nicole Smith
ANS➣Army Nursing Service
ANS➣Agência Nacional de Saúde (National Agency of Suplemental Health; Brazil)
ANS➣Academy of Natural Sciences
ANS➣Ansvarlig Selskap
ANS➣Algemene Nederlandse Spraakkunst (Dutch grammar book)
ANS➣Advanced Networking Software
ANS➣Answer Message
ANS➣Advances in Nursing Science
ANS➣Advanced Network and Services
ANS➣Advanced Neuromodulation Systems
ANS➣Air Navigation System
ANS➣Advanced Network Solutions
ANS➣AirNet Systems (Columbus, OH)
ANS➣American Name Society
ANS➣Alaskan North Slope
ANS➣Advanced Neutron Source
ANS➣Autonomous Navigation System
ANS➣Answer Tone
ANS➣Alaska Native Sisterhood
ANS➣Anthocyanidin Synthase
ANS➣Applied Natural Sciences, Inc. (Hamilton, OH; est. 1993)
ANS➣Authoritative Name Server
ANS➣Application Networking Service (Cisco)
ANS➣Acuerdo de Nivel de Servicio (Spanish: Service Level Agreement)
ANS➣Astronomical Netherlands Satellite
ANS➣American Neurotology Society
ANS➣Advanced Networks and Services
ANS➣Apple Network Server (Apple Computers)
ANS➣Azerbaijan News Service
ANS➣Acorn News Service (mailing list)
ANS➣Alcatel Network Systems
ANS➣Associação Nacional de Sargentos (Portugal - Sargeants National Association)
ANS➣Agentia Nationala pentru Sport (Romania)
ANS➣ATM Name Service
ANS➣Artificial Neural System
ANS➣Adaptive Noise Shaping (DSP, psychoacoustics)
ANS➣Atlantic Nuclear Services Ltd.
ANS➣Area Navigation System
ANS➣Astro-Inertial Navigation System
ANS➣Alternative News Source
ANS➣Archbishop Neale School (Charles County, Maryland)
ANS➣Action Nord Sud Handicap International
ANS➣Actiefront Nationale Socialisten
ANS➣Automatic Notification System
ANS➣Anglican News Service
ANS➣Advanced Narrowband System
ANS➣Anilinonaphthalene Sulfonates
ANS➣Active Network Service
ANS➣American National School
ANS➣Arkansas Numismatic Society
ANS➣Advanced Navigation School
ANS➣Automatic Network Synchronization
ANS➣Aeromedical Neuropsychiatric Standards
ANS➣Anti-Navy Supersonic
ANS➣Async Network Survivability
ANS➣Applications Network Software
ANS➣Ameritech Network Services

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autonomic nervous system

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Pathology

Autonomic nervous system (ANS)

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Synonyms for ANS

noun the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands

Synonyms

Related Words