446 



THE ALIMENTARY CANAL 



[CH. XXVII. 



The upper portion of the pharynx into which the nares open is lined 

 with ciliated epithelium. 



The pharynx is well supplied with mucous glands. 



Between the anterior and posterior arches of the soft palate are 

 situated the Tonsils, one on each side. A tonsil consists of an eleva- 

 tion of the mucous membrane presenting 12 to 15 orifices, which lead 

 into crypts or recesses, in the walls of which are placed nodules of 

 lymphoid tissue (fig. 373). These nodules are enveloped in a less 

 dense adenoid tissue which reaches the mucous surface. The surface 

 is covered with stratified epithelium, and the corium may present 

 rudimentary papillae formed of adenoid tissue. The tonsil is bounded 



^Epithel. 



" I Tunica 

 propria. 



FIG. 373. Vertical section through a crypt of the human tonsil. 1, entrance to the crypt ; 2 and 3, the 

 framework of adenoid tissue ; 4, the enclosing fibrous tissue; a and b, lymphoid nodules; 5 and 6, 

 blood-vessels, (Stohr.) 



beneath by a fibrous capsule (fig. 373, 4). 

 ducts of numerous mucous glands. 



Into the crypts open the 



THE OESOPHAGUS OR GULLET 



The (Esophagus or Gullet, the narrowest portion of the alimentary 

 canal, is a muscular tube, nine or ten inches in length, which extends 

 from the lower end of the pharynx to the cardiac orifice of the 

 stomach. It is made up of three coats viz., the outer, muscular ; 

 the middle, submucous ; and the inner, mucous. The muscular coat 

 is covered externally by a varying amount of loose fibrous tissue. It 

 is composed of two layers of fibres, the outer being arranged longi- 

 tudinally, and the inner circularly. At the upper part of the oeso- 



