THE STOMACH 



111 



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imm. 



^Ffim- 



ported by this membrane are the stomach and the many 

 folded intestines. 



The stomach. — (See Ex. XXXIII.) This organ is a bag- 

 hke swelling (see Fig. 35) of the alimentary canal lying 

 just under the diaphragm and across the upper part of the 

 cavity. The larger end is at the left 

 side of the body, and into its upper 

 surface the esophagus opens by an ori- 

 fice called the cardiac orifice. The right 

 end of the stomach tapers into a narrow 

 neck which is connected with the be- 

 ginning of the small intestine b)^ an 

 opening called the pylorus or ■pyloric 

 orifice. The whole bag is supported in 

 a fold of the peritoneum, whose two 

 parts come together at the lower edge 

 of the stomach and hang down like 

 an apron over the front of the ab- 

 dominal cavity. This apron is known 

 as the greater omentum, and is fre- 

 quently the seat of a great accumula- 

 tion of fat. 



The walls (see Ex. XLI.) of the 

 stomach are composed of four coats or 

 layers. (See Fig. 36.) The outermost is 

 a serous membrane (the peritoneum 

 just mentioned). Next inside this is 

 a muscular coat composed of three 

 layers of muscle fibers. Then comes a layer of connective 

 tissue (the submucous coat), and lining the entire stom- 

 ach is the mucous membrane. The blood vessels of the 

 stomach enter between the folds of the peritoneum, and 



FlO. 36 — Section of 

 stomacla wall; n^ 

 serous membrane 

 (peritoneum) ; I. m., 

 longitudinal m u s- 

 cles ; c. m., cii'cular 

 muscles ; s. m., sub- 

 mucous coat ; m. m., 

 mucous membrane ; 

 d, ducts in mucous 

 membrane. 



