218 



AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



tongue. The secretions of these glands contribute to the formation of the 

 saliva. 



The course of the nerve-fibres supplying the large salivary glands is interest- 

 ing in view of the physiological results of their stimulation. The description 

 here given applies especially to their arrangement in the dog. The parotid gland 

 receive- its fibres from two sources — first, cerebral fibres that originate in the 

 glosso-pharyngeal or ninth cranial nerve, pass into a branch of this nerve known 

 as the tympanic branch or nerve of Jacobsou, thence to the small superficial 

 petrosal nerve, through which they reach the otic ganglion. From this gan- 

 glion they pass by way of the auriculotemporal branch of the inferior max- 



Inferior maxillary 



- branch of fifth 



Glossopharyngeal 

 nerve 



Petro 

 ganglion 



Fig. 51.— Schematic representation of the course of the cerebral fibres to the parotid gland. 



illary division of the fifth cranial nerve to the parotid gland. (A schematic 

 diagram showing the course of these fibres is giveu in Figure 51.) A second 



Facial 



Inferior maxillary 

 branch of fifth 



flinches 



Jto tongue 

 Branches to submaxiU- , 

 lary and sublingual ganglion 



Fig. 52.— Schematic representation of the course of the chorda tympani nerve to the submaxillary gland. 



supply of nerve-fibres is obtained from the cervical sympathetic nerve, the 



fibres reaching the gland ultimately in the coats of the blood-vessels. The 

 submaxillary (and the sublingual) glands receive their nerve-fibres also from 



