Pharyngeal reflex


Pharyngeal reflex

The pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat,cite web |url=http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/09NA.html |title=Medical Neurosciences |format= |work= |accessdate=] evoked by touching the soft palate ["pharyngeal reflex, gag reflex." WordNet 1.7.1. Princeton University, 2001. Answers.com 22 Apr. 2008. http://www.answers.com/topic/pharyngeal-reflex-gag-reflex] , that prevents something from entering the throat except as part of normal swallowing. This helps prevent choking.

The afferent limb of the reflex is supplied by the glossopharyngeal nerve (cranial nerve IX), which inputs to the nucleus solitarius, and the efferent limb is supplied by the vagus nerve (cranial nerve X) from the nucleus ambiguus. Absence of the gag reflex can be a symptom of a number of severe medical conditions, such as damage to the glossopharyngeal nerve, the vagus nerve, or brain death. However, studies indicate that up to one-third of healthy people do not have a gag reflex. [Pharyngeal sensation and gag reflex in healthy subjects. Davies, A., Kidd, D., Stone, S., MacMahon, J. (1995). Lancet 345:487–488]

Swallowing unusually large objects or placing objects in the back of the mouth may cause pharyngeal reflex, and those who frequently experience the reflex will often train themselves to suppress it. In contrast, triggering the reflex is sometimes done intentionally to induce vomiting, for example by those who suffer from bulimia nervosa.

References

External links

* [http://www.dentalfearcentral.org/gagging_dentist.html How to deal with an easily stimulated gag reflex]


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Look at other dictionaries:

  • pharyngeal reflex — noun normal reflex consisting of retching; may be produced by touching the soft palate in the back of the mouth • Syn: ↑gag reflex • Hypernyms: ↑reflex, ↑reflex response, ↑reflex action, ↑instinctive reflex, ↑innate reflex, ↑ …   Useful english dictionary

  • pharyngeal reflex — see gag reflex * * * contraction of the constrictor muscle of the pharynx elicited by touching the back of the pharynx; called also gag r …   Medical dictionary

  • pharyngeal reflex — see gag reflex …   The new mediacal dictionary

  • reflex action — noun an automatic instinctive unlearned reaction to a stimulus • Syn: ↑reflex, ↑reflex response, ↑instinctive reflex, ↑innate reflex, ↑inborn reflex, ↑unconditioned reflex, ↑physiological reaction …   Useful english dictionary

  • reflex response — noun an automatic instinctive unlearned reaction to a stimulus • Syn: ↑reflex, ↑reflex action, ↑instinctive reflex, ↑innate reflex, ↑inborn reflex, ↑unconditioned reflex, ↑physiological reaction …   Useful english dictionary

  • Reflex — A reaction that is involuntary. The corneal reflex is the blink that occurs with irritation of the eye. The nasal reflex is a sneeze. * * * 1. An involuntary reaction in response to a stimulus applied to the periphery and transmitted to the… …   Medical dictionary

  • Reflex — For other uses, see Reflex (disambiguation). A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus.[1] A true reflex is a behavior which is mediated via the reflex arc; this does… …   Wikipedia

  • gag reflex — pharyngeal reflex a normal reflex action caused by contraction of pharynx muscles when the soft palate or posterior pharynx is touched. The reflex is used to test the integrity of the glossopharyngeal and vagus nerves …   The new mediacal dictionary

  • unconditioned reflex — noun an automatic instinctive unlearned reaction to a stimulus • Syn: ↑reflex, ↑reflex response, ↑reflex action, ↑instinctive reflex, ↑innate reflex, ↑inborn reflex, ↑physiological reaction …   Useful english dictionary

  • inborn reflex — noun an automatic instinctive unlearned reaction to a stimulus • Syn: ↑reflex, ↑reflex response, ↑reflex action, ↑instinctive reflex, ↑innate reflex, ↑unconditioned reflex, ↑physiological reaction …   Useful english dictionary


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