THE GLOSSOPHARYNGEAL NERVE. 529 



OTIC OR EAR GANGLION. 



The otic ganglion lies under the foramen ovale, where the in- 

 ferior division of the fifth comes out of the cranium. Its roots 

 are (1) motor; and (2) sensory, from the inferior division of the 

 fifth; and (3) sympathetic, made up of a couple of fine filaments 

 from the plexus, around the meningeal artery. By its branches 

 it communicates with the seventh, chorda tympani, and sends 

 filaments to the parotid gland. 



THE SUBMAXILLARY GANGLION. 



This is on the hyoglossus muscle in close relation to the lin- 

 gual branch of the fifth, from which it gets a sensory root. The 

 chorda tympani passes to the ganglion, carrying efferent impulses 

 through it to the gland. Its sympathetic branches come from 

 the plexus around the facial artery. 



VIII. THE GLOSSOPHARYNGEAL NERVE. 



This nerve, forming part of the eighth pair, springs from the 

 floor of the fourth ventricle above the nucleus of the vagus. It 

 is a mixed nerve, the functions of which may thus be classified. 



Afferent fibres, which are of various kinds, viz. : 



(1.) Sensory fibres, carrying impulses from the anterior surface 

 of the epiglottis, the base of the tongue, the soft palate, the 

 tonsils, the Eustachian tube and tympanum. 



(2.) Excito-motor. This nerve is a very important exciter of 

 reflex movements in swallowing and vomiting, when a stimulus 

 is applied to the glossopalatine arch. 



(3.) Excito-secretory ; the stimulation of the back of the 

 tongue gives rise to a copious flow of saliva by means of reflex 

 action. 



(4.) Taste sensations are, for the most part, carried by this 

 nerve ; they are conveyed from special nerve endings in the back 

 of the tongue (see Taste). 



The efferent fibres are not so varied, being simply motor to the 

 middle constrictor of the pharynx, the stylo-pharyngeus, the 

 elevator of the soft palate, and the azygos uvulae. 

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