CHAPTER XLI. 



THE SALIVARY GLANDS AND THEIR DIGESTIVE 

 ACTION. 



The first of the secretions with which the food comes into contact 

 is the saliva. This is a mixed secretion from the large salivary glands 

 and the small unnamed mucous and serous glands that open into the 

 mouth cavity. 



The Salivary Glands. The salivary glands in man are three 

 in number on each side the parotid, the submaxillary, and 

 the sublingual. The parotid gland communicates with the mouth 

 by a large duct (Stenson's duct) which opens upon the inner 

 surface of the cheek opposite the second molar tooth of the upper 

 jaw. The submaxillary gland lies below the lower jaw, and its 

 duct (Wharton's duct) opens into the mouth cavity at the side of 

 the frenum of the tongue. The sublingual gland lies in the floor of the 

 mouth to the side of the frenum and opens into the mouth cavity by 

 a number (eight to twenty) of small ducts, known as the ducts of 

 Rivinus. One larger duct that runs parallel with the duct of Whar- 

 ton and opens separately into the mouth cavity is sometimes present 

 in man. It is known as the duct of Bartholin and occurs normally in 

 the dog. 



The course of the nerve fibers supplying the large salivary glands 

 is interesting in view of the physiological results of their stimulation. 

 The description here given applies especially to their arrangement 

 in the dog. These glands receive their nerve supply from two general 

 sources, namely, the bulbar autonomics (or cerebral fibers) and 

 the sympathetic autonomics. The parotid gland receives its bulbar 

 autonomic fibers from the glossopharyngeal or ninth cranial nerve; 

 they pass into a branch of this nerve known as the tympanic 

 branch or nerve of Jacobson, thence to the small superficial pe- 

 trosal nerve, through which they reach the otic ganglion. From this 

 ganglion they pass (postganglionic fibers) by way of the auricu- 

 lotemporal branch of the inferior maxillary division of the fifth 

 cranial nerve to the parotid gland (Fig. 255). The sympathetic 

 autonomics pass to the superior cervical ganglion by way of the 

 cervical sympathetic (Fig. 105) and thence as postganglionic fibers 

 in branches which accompany the arteries distributed to the gland. 

 The bulbar autonomic supply for the submaxillary and sublingual 



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