DIGESTIVE GLANDS. 



209 



Intralobular duct. 



shows a distinct longitudinal striation. The inter- 

 calated pieces, on the other hand, are clothed by a 

 single layer of flat, slender, often spindle-shaped 

 cells. The epithelial lining of the acini consists of 

 typical serous-gland cells. This is a single layer 

 of irregular columnar or cubical cells with nuclei 

 situated near their basal portion. When at rest 

 the cytoplasm is filled with zymogen granules 

 which are used up and largely disappear during the 

 process of secretion. Mumps is a specific disease 

 of this gland, more technically known as parotitis. 



2. Sublingual Gland 

 (mucous gland) . This 

 is really a collection of 

 compound tubulo-alve- 

 olar glands. It is an 

 elongated flattened mass 

 one and one-half to 

 one and three-quarter 

 inches in length, situ- 

 ated in the floor of the 

 mouth, one on each side 

 of the median plane, and limited laterally by the 

 ramus of the mandible. Its excretory ducts, from 

 ten to twenty in number, open separately on the 

 summit of papillae visible to the naked eye, which 

 are situated just laterally to the base of the frenum 

 of the tongue. 



The duct system of the gland is similar to that of 

 the parotid, with the exception of the intercalated 

 piece, which is absent. The alveoli are less tubular 

 than those of the parotid and are lined by simple 



A Iveolus. 



Fig. 155. From the parotid gland 

 of man. 



