180 ELEMENTS OF HISTOLOGV. [Chap. xxn. 



239. The framework. Each salivary gland 

 is enveloped in a fibrous connective tissue capsule, 

 in connection with which are fibrous trabeculae and 

 septa in the interior of the gland, by whicnthe sub- 

 stance of the latter is subdivided into lobes, these 

 again into lobules, and these finally into the alveoli 

 or acini. The duct, large vessels and nerves pass 

 to and from the gland by the hilum. The con- 

 nective tissue is of loose texture, contains elastic 

 fibres, and, in some instances more, in others less, 

 numerous lymphoid cells. In the sub-lingual gland 

 they are so numerous that they form continuous rows 

 between the alveoli. The connective tissue matrix 

 between the alveoli is chiefly represented by fine 

 bundles of fibrous tissue, and branched connective 

 tissue corpuscles. 



240. The ducts. Following the chief duct of 

 the gland through the hilum into the interior, we see 

 that it divides into several large branches, according 

 to the number of lobes; each of these breaks ofi 

 into several branches, one for each lobule. Entering 

 the lobule the duct becomes very minute, and passing 

 along it gives off laterally several minute ducts, 

 these are the ititralobular ducts, or the salivary tubes 

 of Pfluger. The larger ducts are called the inter- 

 lobular, and further, interlobar ducts. Each of the 

 latter consists of a limiting membrana propria, 

 strengthened, according to the size of the duct, by 

 thicker or thinner trabeculse of connective tissue. In 

 the chief branches there is present in addition , non- 

 striped muscular tissue. The interior of the duct is 

 a cavity lined with a layer of columnar epithelial 

 cells. In the largest branches there is, outside this 

 layer and inside the membrana propria, a layer of 

 small polyhedral cells. 



241. The intralobular ducts, or the salivary 

 tubes of Pfliiger, consist of a limiting membrana 



