SEROUS ORAL GLANDS. 



189 



Fat cell. 



Alveol 



Intercalated 

 longitudinal se 



duct 



cross sectio 



they are the continuations. The arteries generally follow the ducts from 

 the connective tissue septa into the lobules, where they produce abundant 

 capillary networks close to the basement membranes. The veins derived 

 from these soon enter the interlobular tissue and may then accompany 

 the arteries. Lymphatic vessels also follow the ducts and branch in the 

 interlobular connective tissue where they terminate. Only tissue spaces 

 have been found within the lobules. The nerve supply requires further 

 investigation. Sympathetic nerves from the plexus around the carotid 

 artery accompany the blood vessels into the parotid, and by controlling 

 the blood supply have an important bearing upon secretion. The great 

 auricular nerve, from the second and third cervical nerves, enters the gland, 

 and branches of the facial nerve are involved in it, but branches from the 

 otic ganglion are considered the essential nerves to the gland cells. In the 

 other salivary glands which 

 have been more thoroughly 

 studied, non-medullated 

 fibers from the sympathetic 

 ganglia, either outside of 

 the gland like the otic or 

 from microscopic ganglia 

 along its larger ducts, form 

 plexuses beneath the base- 

 ment membranes. Fibers 

 from these plexuses pene- 

 trate the membranes, 

 within which they form 

 another network before ter- 

 minating in contact with 



the epithelial cells. Their endings may be simple or branched, and 

 are varicose. Free sensory endings of medullated fibers are said to occur 

 in the epithelium of the ducts. 



Mucous Glands. 



The pure mucous glands of the mouth are simple branched alveolo- 

 tubular glands found only on the anterior surface of the soft palate and on 

 the hard palate (palatine glands] , along the borders of the tongue (lingual 

 glands}, and in greater numbers in the root of the tongue. There they 

 may open into the tonsillar pits through ducts lined with columnar epi- 

 thelium, sometimes ciliated. The wall of the tubules consists of a struc- 

 tureless basement membrane and of columnar mucous cells, varying ac- 

 cording to their functional condition as shown in Fig. 208, I-II. The 



Secretory 

 duct, longitu- 

 dinal section, 



cross section. 



FIG. 213. SECTION OF THE PAROTID GLAND FROM A MAN 

 OF 23 YEARS. X 80. 



