WordNet

of nerves and nerve impulses; conveying sensory information from the sense organs to the CNS; "afferent nerves"; "afferent impulses"
any bundle of nerve fibers running to various organs and tissues of the body (同)nervus
control of your emotions; "this kind of tension is not good for my nerves"

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(神経・血管などが)求心性の(末梢(まっしょう)から中枢に向かうこと)
〈C〉『神経』 / 〈C〉《複数形で》『神経過敏』,いらだち / 〈U〉『勇気』,度胸(courage) / 〈U〉《時にa ~》厚かましさ,ずぶとさ;無礼 / 〈C〉葉脈;(昆虫の)翅脈(しみゃく) / 〈人,特に自分〉‘に'力を与える,‘を'元気づける

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/10/24 21:19:26」(JST)

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In the peripheral nervous system, an afferent nerve fiber is the axon of an afferent sensory neuron. It is a long process extending far from the nerve cell body that carries nerve impulses from sensory receptors or sense organs toward the central nervous system. The opposite direction of neural activity is efferent conduction.^[1]^[2]^[3]

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

A touch or painful stimulus, for example, creates a sensation in the brain only after information about the stimulus travels there via afferent nerve pathways. Afferent neurons are pseudounipolar neurons that have a single long axon with a short central and a long peripheral branch. These cells do not have dendrites.^[4] They have a smooth and rounded cell body. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal root known as the dorsal root ganglion.^[5]^[4]

Afferent neurons' somas are located in the ganglia of the peripheral nervous system, and the axons of these cells travel from ganglion to ganglion and lead back to the spinal cord. The majority of these are unipolar neurons in that they have a single axon leaving the cell body and is sent towards the sensory organ.^[5] All of the axons in the dorsal root, which contains afferent nerve fibers, are used in the transduction of somatosensory information. Somatosensory receptors include senses such as pain, touch, temperature, itch, and stretch. For example, a specific muscle fiber called an intrafusal muscle fiber is a type of afferent neuron that lies parallel to the extrafusal muscle fibers thus functions as a stretch receptor by detecting muscle length.^[5] All of these sensations travel along the same general pathway towards the brain, from the dorsal root ganglion they travel to the spinal cord.^[5] From the spinal cord to the medulla, which then leads to the medial lemniscus of the midbrain. From here it travels to the primary somatosensory cortex of the parietal lobe.

Etymology and mnemonics

Afferent is derived from Latin participle afferentem (af- = ad- : to + ferre : bear, carry), meaning carrying into. Ad and ex give an easy mnemonic device for remembering the relationship between afferent and efferent : afferent connection arrives and an efferent connection exits.^[6]

Another mnemonic device used for remembering afferent and efferent (in terms of the spinal cord, with its dorsal/ventral organization) is SAME DAVE. Sensory Afferent Motor Efferent, Dorsal Afferent Ventral Efferent.

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 (5th ed.). Oxford University Press
^ ^a ^b MacCallum, Don. "Peripheral Nervous System". Histology and Virtual Microscopy Learning Resources. University of Michigan Medical School. Retrieved 24 June 2014.
^ ^a ^b ^c ^d Carlson, Neil. Physiology of Behavior. Upper Saddle River, New Jersey: Pearson Education, Inc. ISBN 9780205239399.
^ MedicalMnemonics.com: 3502 3463 367 115

External links

Sensory receptor neurons, a dynamic list of Petilla convention aligned sensory neurons at NeuroLex.

UpToDate Contents

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5. 気道の神経制御 neuronal control of the airways

English Journal

Primary afferent neurons express functional delta opioid receptors in inflamed skin.

Brederson JD1, Honda CN2.
Brain research.Brain Res.2015 Jul 21;1614:105-11. doi: 10.1016/j.brainres.2015.04.023. Epub 2015 Apr 22.
Peripherally-restricted opiate compounds attenuate hyperalgesia in experimental models of inflammatory pain, but have little discernable effect on nociceptive behavior in normal animals. This suggests that activation of opioid receptors on peripheral sensory axons contributes to decreased afferent a
PMID 25911583

Subdiaphragmatic vagotomy enhances stress-induced epinephrine release in rats.

Mravec B1, Ondicova K2, Tillinger A3, Pecenak J4.
Autonomic neuroscience : basic & clinical.Auton Neurosci.2015 Jul;190:20-5. doi: 10.1016/j.autneu.2015.04.003. Epub 2015 Apr 25.
Neuroendocrine stress response is regulated by several feedback loops. Since it has been suggested that afferent vagal pathways contribute to these feedback loops, we examined the effect of surgical subdiaphragmatic vagotomy on both baseline and stress-induced increases in plasma epinephrine, norepi
PMID 25940783

Japanese Journal

Autonomic nervous regulation of ovarian function by noxious somatic afferent stimulation

Uchida Sae,Kagitani Fusako
The journal of physiological sciences 65(1), 1-9, 2015-01
NAID 40020323497

迷走神経を介した消化管ペプチドによる摂食調節

十枝内厚次,Waise TM Zaved,中里雅光
内分泌・糖尿病・代謝内科 39(1), 62-68, 2014-07
NAID 40020175887

Related Pictures

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★リンクテーブル★

リンク元	「求心性神経」
拡張検索	「vagal afferent nerve」「vestibular primary afferent nerve fiber」
関連記事	「afferent」「nerve」「afferents」

「求心性神経」

Afferent nerve fibre
Details
Identifiers
Latin	neurofibrae afferentes
Code	TH H2.00.06.1.00015
TA	A14.2.00.017
FMA	76570
	Anatomical terms of neuroanatomy [edit on Wikidata]