390 



THE DIGESTIVE SYSTEM 



the discharge of the mucus during secretion, is presumably capable of 

 reloading the cell with its mutinous content. 



We will now consider the more important peculiarities of each of 

 the larger salivary glands. 



The Parotid Gland. This is the largestof the salivary glands and 

 in man, sheep, dog, cat and rabbit is purely a serous-secreting organ. 

 However, in sheep, dog and cat it contains also a variable number of 



mucous alveoli during 



Sri 



> *fr~^*N 



the fit 

 geners 

 disapj 

 seconc 

 Traut 



st year ; these de- 

 te and entirely 

 ear during the 

 year (Brock and 

 iann, Anat. Anz., 



47, 17, 1914). 



It is situated^ in 

 front of the external 

 ear^ and overlaps^ in- 

 feriorly both faces of 

 the upper portion of the 

 ramus of the mandible. 

 A variable number of 

 small accessory lobules, 

 including mucus-pro- 

 ducing alveoli, lie along 

 the course of the main 

 parotid ( Stenson's) 



The latter opens into the mouth at the level of the second upper 

 The parotid is invested by a dense fibro-elastic sheath, septa from 

 which divide the gland into lobes and lobules. The lobes and lobules are 

 firmly united by the dense but narrow bands of connective tissue ; these 

 contain the larger ducts, bloodvessels, lymphaticsTand a few small gan- 

 glia. 



The secreting acini are relatively longhand tortuous; they are fre- 

 quently hninched or forked. Because of the relatively low ,height_jif__. 

 their serous-secreting cells the acini appearjslender and their lumen is 

 kreg^Ikr^Jini^ narrow. The 'basket cells' upon which the 



secreting cells rest are highly developed in the parotid and often form 

 a complete investment for the acinus. 



The acini of the parotid are all of one type. The only other tubules 

 within the lobules of this gland are the intercalary and the intralobular 



FIG. 361. FROM A SECTION OF THE HUMAN PAROTID 

 GLAND. 



I, lumen of a serous acinus; sch, intercalary duct; 

 sr, intralobular duct; T, secreting acini. Hematoxy- 

 lin and eosin. X 280. (After Sobotta.) 



duct. 



