244 



HISTOLOGY 



Excretory 

 duct. 



linguae near its front margin. Sometimes this duct is joined by the ductus 

 sublingualis major so that the two have a common outlet. Its orifice may 

 be lined by stratified epithelium, but this soon gives place to the two layered 

 form. Secretory ducts are well developed (Fig. 238) and their basally 



striated cells contain a yellow pigment. The 

 intercalated ducts, which are lined with sim- 

 ple cuboidal epithelium, lead to terminations 

 of two sorts. Most of these consist entirely 

 of serous cells. The others are mixed, but 

 the crescents are small, composed of only a 

 few or even of single serous cells (Figs. 239 

 and 240). Secretory capillaries such as have 

 already been described, are related only to 

 the serous cells. Elastic tissue surrounding 

 intercalated the alveoli has been thought to aid in ex- 

 pelling the secretion through the ducts. The 

 nerves have the same origin as those of the 

 sublingual gland. 



In the oral glands, not infrequently de- 

 generating lobules occur, characterized by 

 abundant connective tissue between tubules with wide lumens and low 

 gland cells. Sometimes they are surrounded by leucocytes. 



Secretory 

 duct. 



ducts. 



End pieces. 



FIG. 238. DIAGRAM OF THE HUMAN 

 SUBMAXILLARY GLAND. 



-' 



Serous gland cells.' 



Intercalated duct. 



Mucous 

 gland cells. 





Secretory duct. 



FIG. 239. SECTION OF THE SUBMAXILLARY GLAND OF AN ADULT MAN. X asa. 



