DIGESTION 



99 



represent the upper border ; to represent the lower border the 

 same two points are joined by a bold curve, bulging upwards 

 to the nipple, outwards to the side of the body, and down- 

 wards some distance on the abdomen (cf. Fig. 2). 



Such an outline represents the form and position of the 

 stomach when distended ; but it is to be understood that 

 its dimensions depend upon the amount of its contents. 

 It is capable of holding about 7 pints. The junction of 



FIG. 6. 



The stomach has been cut across a short distance from the pytoric valve, and removed, to show 

 the viscera which lie behind it. The descending aorta and the vena cava rest upon the ver- 

 tebral column. They are crossed by the pancreas and the transverse portion of the 

 duodenum. The head of the pancreas is enclosed by the curvatures of the duodenum. 

 The ducts of the liver and pancreas are seen entering the descending duodenum side by 

 side. 



resophagus and stomach is closed by a muscular ring, or 

 sphincter muscle the cardiac sphincter ; the junction of 

 stomach and intestine is guarded by a much stronger pyloric 

 sphincter The average diameter of the small intestine is 

 about 1J inches. It is wide enough, therefore, to admit two 

 fingers. The length of the tube is about 22 feet. Its first 

 part is termed the " duodenum," because its length equals 

 the breadth of twelve fingers i.e., about 9 inches. The 

 remainder is divided arbitrarily into jejunum and ileum. The 



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