DIGESTION. 



47 



the rest of the intestinal tract ; it is hollow, having a peritoneal cov- 

 ering and a mucous membrane lining, with a muscular layer between. 

 It is in this mucous membrane that the special function of the stom- 

 ach lies, for here are found glands which secrete the gastric juice. 

 The active peristaltic motion churns the food about after deglutition, 

 and exposes it thoroughly to the action of the digestive agents. The 

 function of the stomach is the digestion of proteids. 



Describe the glands of the stomach. 



If one looks closely at the mucous surface of the stomach, it 

 is seen to present a sort of reticulated (Fig. 7) appearance, the 

 meshes being larger at the pyloric than at the cardiac end of the 

 stomach. It is in the interstices 



of this mesh that the glands FIG. 8. 



open. The openings are smaller 

 at the cardiac than at the pyloric 

 end, and the character of the 

 glands changes : we therefore 

 speak of two varieties of gastric 

 glands 1, peptic; 2, pyloric. 



1. The peptic glands are ar- 

 ranged in groups throughout the 

 stomach, but not so abundantly 

 at the pyloric end. They often 

 consist of a simple tube dipping 

 into the surface and lined with 

 columnar epithelium (Fig. 8), but 

 they may be branched i. e. sev- 

 eral glands may empty into a 

 common duct. The columnar epi- 

 thelium in the deeper portion of 

 the gland contains large, almost 

 globular, cells, which are known 

 as peptic cells. 



2. The pyloric glands, or mu- 

 cous glands, like the peptic, may 

 be simple or compound. The 

 ducts are larger, and the large 

 cells are wanting (Fig. 9). Dur- 

 ing digestion the cells of both 



Varieties of glands become swoll- 



Compound Gastric Follicle, from the car- 

 diac portion of the human stomach: 1, 

 excretory tubes leading to the surface; 

 2, tubercular follicles containing sphe- 

 roidal cells (Kolliker). 



