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Author Topic: what events occur during deglutination?  (Read 9047 times)

Offline 118

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what events occur during deglutination?
« on: 20/12/2005 14:51:17 »
what is their neural control? i know it must move the bolus and protect the respiratory tract (i.e. for example the closing of the glottis) but how does it do this? HELP PLEASE


 

Offline yeliab_cram

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Re: what events occur during deglutination?
« Reply #1 on: 04/01/2006 15:36:04 »
Deglutination begins with the voluntary chewing of food which is softened and formed it into a bolus within the oral cavity. The bolus is then forced backwards in the oral cavity and into the oropharynx. This action is produced by the tongue pushing against the hard pallate (an action brought about by the contraction of styloglossus muslce). Once the bolus of food hits the oropharynx it stimulates tactile receptors - from this moment, involuntary mechanisms take over, governed by the swallowing centre in the medulla.

The next stage in involuntary and involves the rapid shutting off of the alternative exit routes from the oropharynx in order to ensure the bolus of food passes in the right direction. For this to occur the nasopharynx must be shut off (achieved by raising the soft palate via activation of levator and tensor veli palitini muscles)and the larynx elevated to close of the trachea (this is achieved by activation of the suprahyoid muscles, which lift the larynx and cause the epiglottis to shut) the longitudinal muscles on the outside of the pharynx also contract in order to widen the path towards the oesophagus. The bolus of food is then propelled towards the stomach be sequential contractions of first the pharyngeal constrictors and then the oesophageal constrictors.

During this process, the respiratory centre in the medulla is beiefly inhibited by the swallowing centre preventing inspiration during the quick act of swallowing. This is called deglitination apnoea.
 

Offline 118

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Re: what events occur during deglutination?
« Reply #2 on: 05/01/2006 19:23:31 »
thanks mate that helps alot
 

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Re: what events occur during deglutination?
« Reply #2 on: 05/01/2006 19:23:31 »

 

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