The pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat,[1] evoked by touching the soft palate[2], that prevents something from entering the throat except as part of normal swallowing. A reflex action, also known as a reflex, is an involuntary and almost instant movement in response to stimulus. The soft palate (or velum, or muscular palate) is the soft tissue constituting the back of the roof of the Mouth. Swallowing, known scientifically as deglutition is the process in the human or animal body that makes something pass from the Mouth, to the Pharynx, into This helps prevent choking. Choking is the mechanical obstruction of the flow of air from the environment into the lungs
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. The glossopharyngeal nerve is the ninth of twelve pairs of Cranial nerves. The solitary nucleus and tract are structures in the Brainstem that carry and receive visceral sensation and Taste from the facial (VII The vagus nerve (ˈveɪˌgəs (VĀ-gəs (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired Cranial nerves, and is the The nucleus ambiguus (literally "ambiguous nucleus" is a region of histologically disparate cells located just dorsal ( Posterior) to Absence of the gag reflex is a symptom of a number of severe medical conditions, such as damage to the glossopharyngeal nerve, the vagus nerve, or brain death. The glossopharyngeal nerve is the ninth of twelve pairs of Cranial nerves. The vagus nerve (ˈveɪˌgəs (VĀ-gəs (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired Cranial nerves, and is the Brain death is a legal definition of death that emerged in the 1960s as a response to the ability to resuscitate individuals and mechanically keep the heart and lungs working
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. Bulimia nervosa is an Eating disorder characterized by recurrent Binge eating, followed by compensatory behaviors referred to as "purging"
References
- ^ Medical Neurosciences.
- ^ "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
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