THE SALIVARY GLANDS. 



257 



Of the blood-vessels, which are abundant, the larger lie in the submucosa, 

 while the smaller penetrate into the papillae, in which they form either capillary 

 networks or simple loops. 



Of the lymph-vessels the larger trunks, which form a coarse meshwork, lie in 

 the submucosa, while the smaller, forming a finer network, pass through the mucous 

 membrane itself. The cutaneous follicles or lymph-follicles constitute a part of 

 the lymphatic apparatus. They form an almost coherent layer on the back of the 

 tongue at its root. Several of these lymph-follicles always collect into a round 

 mass, surrounded by connective tissue, and raising . the mucous membrane 

 somewhat. In the center of every such collection is a depression (Fig. 93) into the 

 bottom of which mucous glands empty and fill thesmall crater with mucous secretion. 



The tonsils exhibit on the whole the same formation, crypt-like depressions, 

 into the sinuses of which small mucous glands empty, and surrounded by masses of 

 from 10 to 20 lymph-follicles. Layers of firm connective tissue form a sheath about 

 the tonsils. The pharyngeal and tubal tonsils exhibit a similar structure. 



Many medullated nerve-fibers, coming from the submucous tissue, ramify in 

 the mucous membrane and terminate in part in separate papillas in the form of 

 Krause's end-bulbs, in larger number on the lips and the soft palate, in smaller 

 number on the cheeks and the floor of the mouth. Probably the nerves also 

 spread out in the form of fine terminal nodules between the epithelial cells, accord- 

 ing to the Cohnheim-Langerhans mode of distribution. Functionally these are 

 sensory nerves and nerves of touch. 



THE SALIVARY GLANDS. 



The salivary glands and also the pancreas are compound tubular 

 glands. The excretory ducts, formed of connective and elastic tissues 

 (Wharton's duct contains also unstriated muscle-fibers) are lined with 



Fio. 94 .-Histolo g y of the Salivary GUu: J^J j 



ti^S^^^^ 



Into the structureless membrane of the acinus 

 incorporated a layer V^ 



cells (Fig. 94, D). Next to the outer wall of the acinus 

 17 



