CHAPTER XIIL 



THE DIGESTIVE TRACT. 



THE; MOUTH. 



The mouth is lined with a mucous membrane con- 

 sisting of stratified epithelial cells. Upon the surface 

 of the mouth are seen the ducts of numerous glands. 

 Between this layer of epithelial cells and the submu- 

 cous tissue are found the papillse of the mouth. They 

 are composed of fibrous tissue. The gums have no 

 glands in them. The blood supply is derived from the 

 mucous membrane blood supply. The lymphatics are 

 from the same source. 



THE: 



The teeth are said by some to be a part of the tegu- 

 mentary system. The structure of a grown tooth is as 

 follows : every tooth has a neck, crown and root. The 

 crown is composed of a modified epithelial cell tissue, 

 called enamel. The enamel is the hardest substance 

 in the body, and is covered by a membrane of epithelial 

 (92) 



