178 



MOUTH DIGESTION. 



each having a distinct function ; one vasodilator and the other 

 secretory. There are also two sets of fibers in the sympathetic 

 nerves which supply these glands : One vasoconstrictor i. e., when 



FIG. 101. Schematic representation of the course of the cerebral fibers to the 



parotid gland. 



stimulated the blood-vessels are constricted ; and the other secre- 

 tory. It is, however, mainly through the chorda tympani that the 

 impulses pass which cause secretion. 



FIG. 102. Schematic representation of the course of the chorda tympani nerve to 

 the submaxillary gland. 



The glossopharyngeal fibers, which have already been traced to 

 the parotid gland, convey the impulses which cause secretion in 

 this gland. The sympathetic nerves are vasoconstrictor in func- 

 tion. 



