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of nerves and nerve impulses; conveying information away from the CNS; "efferent nerves and impulses" (同)motorial

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(血管・導管が)輸出性の,導出性の;(神経が)遠心性の
神経単位,神経細胞,ニューロン,ノイロン

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2018/03/22 08:06:09」(JST)

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In the peripheral nervous system, an efferent nerve fiber is the axon of a motor neuron. The nerve fiber is a long process projecting far from the neuron's body that carries nerve impulses away from the central nervous system toward the peripheral effector organs (mainly muscles and glands). A bundle of these fibers is called a motor nerve or an efferent nerve.

The opposite direction of neural activity is afferent conduction,^[1]^[2]^[3] which carries impulses by way of the afferent nerve fibers of sensory neurons.

In the nervous system there is a "closed loop" system of sensation, decision, and reactions. This process is carried out through the activity of sensory neurons, interneurons, and motor neurons.

Motor nerve

Myelinated GS efferent fiber leaving cell body of motor neuron to form a neuromuscular junction

The efferent nerve fibers of motor neurons are involved in muscle control, both skeletal and smooth muscle. The cell body of the motor neuron is connected to a single, long axon and several shorter dendrites projecting out of the cell body itself. This axon then forms a neuromuscular junction with the effectors. The cell body of the motor neuron is satellite-shaped. The motor neuron is present in the grey matter of the spinal cord and medulla oblongata, and forms an electrochemical pathway to the effector organ or muscle. Besides motor nerves, there are efferent sensory nerves that often serve to adjust the sensitivity of the signal relayed by the afferent sensory nerve.^{[citation needed]}

Types

There are three types of efferent fibers: general somatic efferent fibers (GSE), general visceral efferent fibers (GVE) and special visceral efferent fibers (SVE).

Subtypes of these fibers include (GSE): alpha motor neurons (α) – these target extrafusal muscle fibers, and gamma motor neurons (γ) that target intrafusal muscle fibers. Beta motor neurons target both types of muscle fiber and there are two types known as static and dynamic.

Etymology and mnemonics

Both afferent and efferent come from French, evolved from Latin (the basis of many terms in medicine and biology) for the terms, respectively, ad ferens (Latin verb ferre: carry), meaning carrying into, and ex ferens, meaning carrying away (ad literally means to, and e = ex means from). Ad and ex give an easy mnemonic device for remembering the relationship between afferent and efferent: afferent connection arrives and an efferent connection exits.^[4]

Afferent and efferent are connected to affect and effect through their common Latin roots: Afferent nerves affect the subject, whereas efferent nerves allow the subject to effect change.

References

^ Mader S. S. (2000): Human biology. McGraw-Hill, New York, ISBN 0-07-290584-0; ISBN 0-07-117940-2.
^ Hall J. E., Guyton A. C. (2006): Textbook of medical physiology, 11th edition. Elsevier Saunders, St. Louis, Mo, ISBN 0-7216-0240-1.
^ Warrell D. A., Cox T. M., Firth J. D. (2010): The Oxford Textbook of Medicine Archived 2012-03-21 at the Wayback Machine. (5th ed.). Oxford University Press
^ MedicalMnemonics.com: 3502 3463 367 115

External links

Motor neurons, a dynamic list of Petilla convention aligned motor neurons at NeuroLex.

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UpToDate Contents

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1. 筋萎縮性側索硬化症およびその他の運動ニューロン疾患の臨床的特徴 clinical features of amyotrophic lateral sclerosis and other forms of motor neuron disease
2. 成人における詳細な神経学的検査 the detailed neurologic examination in adults
3. 筋萎縮性側索硬化症およびその他の運動ニューロン疾患の診断 diagnosis of amyotrophic lateral sclerosis and other forms of motor neuron disease
4. 重症筋無力症の鑑別診断 differential diagnosis of myasthenia gravis
5. 筋萎縮性側索硬化症の疫学および病因 epidemiology and pathogenesis of amyotrophic lateral sclerosis

English Journal

Genetic labeling of steroidogenic factor-1 (SF-1) neurons in mice reveals ventromedial nucleus of the hypothalamus (VMH) circuitry beginning at neurogenesis and development of a separate non-SF-1 neuronal cluster in the ventrolateral VMH.

Cheung CC, Kurrasch DM, Liang JK, Ingraham HA.SourceDepartment of Pediatrics, University of California, San Francisco, California 94143. ccheung@chla.usc.edu.
The Journal of comparative neurology.J Comp Neurol.2013 Apr 15;521(6):1268-88. doi: 10.1002/cne.23226.
The ventromedial nucleus of the hypothalamus (VMH) influences a wide variety of physiological responses. Here, using two distinct but complementary genetic tracing approaches in mice, we describe the development of VMH efferent projections, as marked by steroidogenic factor-1 (SF-1; NR5A1). SF-1 neu
PMID 22987798

Roux-en-Y Gastric Bypass reverses the effects of diet-induced obesity to inhibit the responsiveness of central vagal motoneurones.

Browning K, Fortna SR, Hajnal A.SourcePenn State College of Medicine.
The Journal of physiology.J Physiol.2013 Mar 4. [Epub ahead of print]
Diet-induced obesity (DIO) has been shown to alter the biophysical properties and pharmacological responsiveness of vagal afferent neurones and fibers, although the effects of DIO on central vagal neurones have never been investigated. The aims of this study were to investigate whether high-fat diet
PMID 23459752

Japanese Journal

Orexin neurons suppress narcolepsy via 2 distinct efferent pathways

Journal of Clinical Investigation 124(2), 604-616, 2014-02
NAID 120005411681

発熱及び体温調節の交感神経経路

自律神経 = The Autonomic nervous system 43(1), 44-51, 2006-02-15
NAID 10017503307

緩和医療とその治療：麻酔科医はどうかかわるか　　関連痛を念頭においたがんの痛みの診断

日本臨床麻酔学会誌 26(5), 561-569, 2006
NAID 130004449586

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関連記事	「efferent」「neuro」「efferents」

「efferent」

Efferent nerve fiber
Details
System	Peripheral nervous system
Identifiers
Latin	neurofibrae efferentes
TA	A14.2.00.018
TH	H2.00.06.1.00016
FMA	76571
	Anatomical terms of neuroanatomy [edit on Wikidata]