DIGESTION. 



167 



Whenever these centers are stimulated, either by nerve impulses 

 coming through afferent nerves, from the periphery or from the 

 brain, impulses are generated which pass outward through efferent 

 nerves the chorda tympani nerve to the submaxillary and sublingual 

 glands, and the auriculo-temporal nerve to the parotid gland. 



The chorda tympani nerve is a branch of the facial, the trunk of 

 which it leaves in the aqueduct of Fallopius. It then crosses the 

 tympanic cavity, emerges through the glaserian fissure, and joins 

 the lingual branch of the inferior maxillary division of the fifth 



Parotid ,. s ....;. 



Gland -fe; 



Superior..... 

 Cervical 

 Ganglion 



FIG. 67. SCHEME OF THE NERVES INVOLVED IN THE SECRETION OF SALIVA. 



nerve. After passing forward as far as the sublingual gland, nearly 

 all of the original fibers leave the lingual nerve by four or five strands 

 to become connected by terminal branches with nerve-ganglion cells in 

 relation with the submaxillary and sublingual glands. (See Fig. 67.) 

 The nerve-fibers which conduct nerve impulses outward from 

 the medulla to the parotid gland are believed to pass through the 

 glossopharyngeal nerve, through the tympanic branch or nerve of 

 Jacobson, to the otic ganglion, with which they become connected. 



