668 TEXT-BOOK OF PHYSIOLOGY 



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believed that these fibers are derived originally from the efferent fibers of tl 

 glosso-pharyngeal nerve. The remaining fibers of the superior larynge 

 endow the upper portion of the larynx with extreme sensibility which to 

 certain extent protects the air-passages against the entrance of forei^ 

 bodies. Irritation of the terminal filaments of this nerve by particles 

 food, solid or liquid, gives rise to marked reflex spasm of the adduct< 

 muscles and closure of the glottis, followed by a strong expiratory blast of a 

 from the lungs by which the offending particles are removed. Division 

 this nerve on both sides is followed by a paralysis of the crico-thyroid muscle 

 a lowering of the tension of the vocal bands, and a loss of sensibility of tl 

 laryngeal mucous membrane. 



