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m (Dr Joe Kiff moved page A delta fiber to A delta fibers)
 
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Name = A delta fiber |
 
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'''A delta fibers''' ('''Aδ''') are the fibers which convey fast [[pain]] information.
 
   
They are much faster than the [[C fiber]]s because they are [[myelin]]ated, but they are much thinner than other "A" caliber nerve fibers, so they conduct signals more slowly than the other fibers of that class.
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'''A delta fibers''', or fibers, are a [[type of sensory fiber]].
   
The fibers terminate at [[Rexed lamina]] I.
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They respond to stimuli such as cold and pressure, and as [[nociceptors]] stimulation of them is interpreted as fast/first [[pain]] information.
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They are thinly [[myelin]]ated, thus they send impulses faster than unmyelinated [[C fiber]]s, but more slowly than other, more thickly myelinated "A" class fibers.
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The fibers terminate at [[Rexed lamina|Rexed laminae]] I and V.<ref>Basbaum et al. 2009. Cellular and Molecular Mechanisms of Pain. Cell 139. DOI 10.1016/j.cell.2009.09.028 - Available at http://ac.els-cdn.com/S0092867409012434/1-s2.0-S0092867409012434-main.pdf?_tid=1ad886f0258c3fb66e249ad7a37df3e2&acdnat=1337524198_340d33507bdc41242daa6a3a72b2cf0a</ref>
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==Structure==
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They are thin (2 to 5 μm in diameter), [[myelin]]ated [[axons]] with a moderate [[conduction velocity]], or speed of travel of a nerve signal (2 to 30 m/s). These [[nerve]] fibers are associated with acute (sharp) [[Pain and nociception|pain]] and therefore constitute the [[afferent nerve fiber|afferent]] portion of the [[reflex arc]] that results in "pulling away" from noxious stimuli (e.g. retracting your hand away from a hot stove). A certain proportion of Aδ fibers are also associated with sensations of [[temperature]] (also known as '[[cold receptors]]' in [[mammals]]) and [[pressure]]. Slowly-conducting, unmyelinated [[C fiber]]s, by contrast, carry slow, burning pain.
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Like other sensory fibers, the Aδ fiber is an extension of a [[pseudounipolar neuron|pseudounipolar]] [[neuron]] with its [[cell body]] located in a [[dorsal root ganglion]] or trigeminal ganglion. Within the [[spinal cord]], afferent [[Pain and nociception|nociceptor]] fibers [[synapse]] at or near the spinal cord level where they enter.
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==See also==
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* [[Free nerve ending]]
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* [[Thermoreceptor]]
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==References==
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{{Reflist}}
   
 
==External links==
 
==External links==
* http://instruct1.cit.cornell.edu/courses/psych396/student2006/the_biology_of_pain_mac_version/functions.html
 
   
 
{{Nervous tissue}}
 
{{Nervous tissue}}
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[[Category:Neuroanatomy]]
 
[[Category:Neuroanatomy]]
 
[[Category:Pain]]
 
[[Category:Pain]]
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{{enWP|A delta fiber}}

Latest revision as of 06:42, October 16, 2013

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A delta fiber
Medulla spinalis - Substantia grisea - English
A delta fiber not labeled, but fibers terminate at Rexed lamina I, labeled at upper left.
Latin '
Gray's subject #
System
MeSH [1]
[[Image:|190px|center|]]

A delta fibers, or Aδ fibers, are a type of sensory fiber.

They respond to stimuli such as cold and pressure, and as nociceptors stimulation of them is interpreted as fast/first pain information.

They are thinly myelinated, thus they send impulses faster than unmyelinated C fibers, but more slowly than other, more thickly myelinated "A" class fibers.

The fibers terminate at Rexed laminae I and V.[1]

StructureEdit

They are thin (2 to 5 μm in diameter), myelinated axons with a moderate conduction velocity, or speed of travel of a nerve signal (2 to 30 m/s). These nerve fibers are associated with acute (sharp) pain and therefore constitute the afferent portion of the reflex arc that results in "pulling away" from noxious stimuli (e.g. retracting your hand away from a hot stove). A certain proportion of Aδ fibers are also associated with sensations of temperature (also known as 'cold receptors' in mammals) and pressure. Slowly-conducting, unmyelinated C fibers, by contrast, carry slow, burning pain.

Like other sensory fibers, the Aδ fiber is an extension of a pseudounipolar neuron with its cell body located in a dorsal root ganglion or trigeminal ganglion. Within the spinal cord, afferent nociceptor fibers synapse at or near the spinal cord level where they enter.

See alsoEdit

ReferencesEdit

  1. Basbaum et al. 2009. Cellular and Molecular Mechanisms of Pain. Cell 139. DOI 10.1016/j.cell.2009.09.028 - Available at http://ac.els-cdn.com/S0092867409012434/1-s2.0-S0092867409012434-main.pdf?_tid=1ad886f0258c3fb66e249ad7a37df3e2&acdnat=1337524198_340d33507bdc41242daa6a3a72b2cf0a

External linksEdit


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