The Digestion of Food 



107 



intes 



intestine begins is known as \hzpyloric orifice. It is guarded 

 by a kind of valve, known as the pylorus, or gatekeeper. 



160. Coats of Stomach. The walls of the stomach are 

 formed of four coats, known successively from without as 

 serous, muscular, submucous, 



and mucous. The outer coat 

 is the serous membrane 

 which lines the abdomen, 

 the peritoneum (sec. 167). 

 The second coat is muscular, 

 having three sets of involun- 

 tary muscular fibers. The 

 third coat (submucous) is 

 made up of loose connective 

 tissue. Lastly, the mucous 

 coat, a moist, pink, inelastic 

 membrane, completely lines 

 the stomach. When the 

 stomach is not distended the 

 mucous layer is thrown into 

 folds presenting a corrugated 

 appearance. 



161. The Gastric Glands. 

 If we were to examine with 

 a hand lens the inner sur- 

 face of the stomach, we 

 should find it covered with 



little pits, or depressions. 



FIG. 51. A View into the Back Part 

 of the Adult Mouth. 



These" are the Openings Of < Th * head is represented as having been 



thrown back, and the tongue drawn for- 



the gastric glands (Fig. 53). ward.) 



Soon after food enters A > #> incisors ; C, canine; D, ^bicuspids; 



F, //, PC, molars ; M, anterior pillar of the 

 fauces ; N, tonsil ; L, uvula ; O, upper 

 part of the pharynx ; P, tongue drawn 

 forward ; J?, linear ridge, or raphe. 



the stomach, drops of fluid, 

 known as gastric juice, col- 

 lect at the mouths of these 

 glands and trickle down its walls to mix with the food 

 and to aid in its digestion. 



