242 HISTOLOGY 



serous cells such as are to be described in the largest glands of this group 



the sublingual and submaxillary. 



The sublingual glands are two groups of glands, one on either side of 



the median line, under the mucous membrane in the front of the mouth. 



The largest component is an alveolo-tubular structure emptying by the 



ductus sublingualis major on the side of the 

 frenulum lingua. The main stem and the 

 principal branches of the large sublingual duct 

 are lined by a two-layered or pseudostratified 

 columnar epithelium, as in the parotid duct. 

 They are surrounded by connective tissue con- 

 taining many elastic fibers. Ducts less than 

 .05 mm. in diameter have a simple columnar 

 epithelium, which in a few places becomes low 

 and basally striated to form the secretory 

 ducts. As shown in the diagram, Fig. 235, the 

 secretory ducts are very short, and they are 

 accordingly infrequent in sections; the slender 

 intercalated ducts are absent. The terminal 



FIG. 235. DIAGRAM OF THE HUMAN secreting portions of the gland are somewhat 



SUBLINGUAL GLAND. .^ . , 



tortuous structures, often presenting outpock- 



etings. They consist of mucous and serous cells quite evenly mixed, so 

 that the gland has a characteristic appearance under low magnification 

 (Fig. 236). The serous cells sometimes border upon the lumen, but often 

 they are separated from it by the mucous cells so that they form crescents 

 (Fig. 237). Only the serous cells are provided with the branched inter- 

 cellular secretory capillaries. Around the tubules there is a basement 

 membrane including certain stellate cells. The interlobular connective 

 tissue contains many lymphocytes. 



Near the gland just described, but apparently quite distinct from it, 

 there is a group of 5 to 20 alveolo-tubular glands which open by separate 

 ducts, the ductus sublinguales minores. These glands consist almost ex- 

 clusively of mucous cells. 



The sublingual gland as a whole receives fibers from the submaxillary 

 ganglion, and so from the chorda tympani, which passes > to this ganglion 

 by way of an anastomosis with the lingual branch of the mandibular nerve. 

 Its ducts are said to have sensory fibers, probably derived from the lingual 

 nerve. Sympathetic fibers from the superior cervical ganglion, which 

 have ascended the neck as perivascular plexuses, extend to the sublingual 

 gland around its arteries. 



The submaxillary glands are a pair of branched alveolar glands, in part 

 tubulo-alveolar, found in the floor of the mouth, each being drained by a 

 submaxillary duct (Wharton's) which opens on the sides of the frenulum 



