106 



ADVANCED PHYSIOLOGY 



Coeciim 



Sma/f 

 /nfesfine 



From the lower end of the ccecum protrudes a short hollow 

 tube called the vermiform appendix; this varies in size in 

 different people but it is usually from 

 three to six inches long, and a quarter 

 of an inch or more in diameter. The 

 cavity opens into the coecum. 



Beyond the lower end of the descend- 

 ing colon the intestine passes into an 

 S-shaped portion called the sigmoid 

 flexure; from this all intestinal contents 

 enter the final section of the digestive 

 tract, the rectum. This opens to the 

 exterior by the anal aperture; Fig. 52. 

 The walls of the large intestine are 

 constructed practically like those of the 

 small; but there seem to be no glands 

 opening into it which are concerned 

 with the digestion of food, though 

 mucous glands are numerous. The food may not be wholly 

 digested in the small intestine and so digestive processes, 

 to a small extent, go on here although not by virtue of 

 the glands of the large intestine itself. There is also very 

 rapid absorption from this region, particularly of water, and 

 this causes the intestinal contents to become more and more 

 hard. Much of this " undissolved food " performs a valuable 

 service, however, by mechanically stimulating the walls of 

 the intestine and thus causing more rapid peristaltic action. 

 A more certain passing along of food materials is thus ensured 

 and so the trouble called constipation is, in a measure, pre- 

 vented. If only very fine foods, e. g. those made from 

 finely powdered flours, are eaten, the water in them may be 

 absorbed quickly and then the mass becomes so dry and 

 unyielding that it is forced along the canal with great diffi- 

 culty. Coarse foods, which are sometimes refused by persons 

 who proudly consider them top crude and cheap for their 



Vermiform 

 Appendix. 



FIG. 58. THE BEGIN- 

 NING OF THE LABGE 

 INTESTINE 



Showing the opening 

 from the small intestine 

 at some distance from 

 its end. 



