HISTOLOGY 115 



Blood vessels ramify in the interlobar connective tissue. They follow 

 the course of the ducts, and a capillary network provides the tubules and 

 alveoli with a rich blood supply. 



Major sublingual glands. — The major sublingual glands are in close 

 proximit}' to the lateral surface of the submaxillary glands. 





-Intralobular 

 duct 





Fig. 51. — -Sublingual gland. (X200.) 



Loewenthal (69) referred to this gland as the retrolingual gland and con- 

 sidered it to be an accessory submaxillary gland. It is composed usually of 

 one large lobe divided into smaller lobules by connective tissue septa. 

 The main excretory duct is lined by pseudostratified columnar epithelium 

 and has a parallel course with the duct of the submaxillary gland. It opens 

 through a separate orifice in close proximity to the submaxillary duct. The 

 intralobular ducts are striated tubules and are lined by rodded epithelium. 

 The short and narrow intercalated ducts are lined by very low cuboidal 

 epithelial cells. In the mucous cells which constitute the alveoli the 

 nuclei are flattened to the bases and the cytoplasm appears clear and 

 slightly basophilic. Stained with thionin the cells contain a purple-red, with 

 Mayer's mucicarmine a red network of precipitated mucigen. The delicate 

 basement membrane and stellate basal cells are like those described in the 

 submaxillary gland (Fig. 51). 



Parotid glands. — The paired parotid glands are composed of several 

 small elongated lobules. Extending from the ventro-lateral surface of the 

 neck, the posterior lobes reach the shoulders. The main duct is formed by 

 several branches and opens in the oral cavity opposite the molar teeth (43). 

 The intralobular ducts are striated tubules, lined by rodded epithelial cells. 

 The intercalated ducts are lined by low cuboidal epithelial cells. The serous 

 cells of the secretory alveoli are pyramidal in shape. Around and below 



