1 90 ELEMENTS Of HISTOLOGY. [Chap, xxi 



the palate and uvula (levator and tensor palati), and 

 the arcus palato-pharyngeus, and palato-glossus. 



256. The last branches of the arteries break up in 

 a dense capillary network on the surface of the mucosa, 

 and from it loops ascend into the papillae. Of 

 course, fat tissue, glands, and muscular tissue re- 

 ceive their own supply. There is a very rich plexus 

 of veins in the superficial part of the mucosa. They are 

 conspicuous by their size and the thinness of their wall. 



The lymphatics form networks in all layers of the 

 mucosa, including the papillae. The large efferent 

 trunks are situated in the submucosa. The last 

 outrunners of the nerve branches form a plexus of non- 

 medullated fibres in the superficial layer of the mucosa, 

 whence numerous primitive fibrillce ascend into the 

 epithelium to form networks. Meissner's tactile cor- 

 puscles have been found in the papillae of the lips and 

 in those of the tongue. 



257. In the pharynx the relations remain the 

 same, except in the upper or nasal part, where 

 we find many places covered with columnar ciliated 

 epithelium. As in the palatine tonsils so also here, 

 the mucosa is infiltrated with diffuse adenoid tissue, 

 and with lymph follicles in great numbers. This 

 forms the pharyngeal tonsil of Luschka. 



In the palatine tonsil and in the pharyngeal tonsil 

 there are numerous crypts leading from the sur- 

 face into the depth. This is due to the folding of 

 the infiltrated mucosa. Such crypts are, in the 

 pharynx, sometimes lined all through with ciliated epi- 

 thelium, although the parts of the free surface around 

 them are covered with stratified pavement epithelium. 



258. The tongue is a fold of the mucous 

 membrane. Its bulk is made up of striped muscular 

 tissue (genio-, hyo-, and stylo-glossus ; according to 

 direction : longitudinal is superior and inferior, and 

 transversus linguse). The lower surface is covered 



