Scratch reflex

The scratch reflex is a reflextransmitted by very sensitive nerve endingsnear the surface of the skinvia the spinal cord, and is a reflex frequently inherited by mammals. The nerve signalincludes positioning to pinpoint the location of the itch, and the effect of the reflex is either an affective sensationor even an involuntary action to make a scratching movement that usually relieves the itch. The scratch reflex is a reflex to help an organism protect and rid its body of parasitesand other irritants.

In case of intense itch, scratching to relieve it can cause pain, and such pain signals are believed to suppress the itch signals due to a lateral inhibition effect, as the dorsal column systemtransmits critical sensations much faster than the cruder spinothalamic tractthat deals with less accurate types of sensations, such as itch, also at a slower pace.

See also

• Central nervous system

References

• {{news reference

| firstname=S. | lastname=Palaniappan | url=http://www.hindu.com/seta/2004/02/12/stories/2004021200241500.htm | title=Sci Tech: Scratch reflex | org=The Hindu | date=2004-02-12 | urldate=2005-12-16 }}

• {{web reference

| author=Bernard Spilman
| title=Neurological background: Ascending Spinal Tracts
| work=Neurokinesiology
| url=http://www.neurokinesiology.org/Neurological_Background/ascending_spinal_tracts.html
| date=2005-12-16

}}

• {{web reference

| author=Various
| title=Why do dogs shake their legs when you scratch their belly?
| work=Google Answers
| url=http://answers.google.com/answers/threadview?id=581270
| date=2005-12-16
| publishyear=October 17, 2005

}}

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Scratch+reflex Wikipedia article Scratch reflex.