DIGESTIVE SYSTEM. 



201 



Mucosa. 



disappear and the intestine becomes about one foot 

 longer. 



Appendices epiploiccz are small pedunculate proc- 

 esses that project from the serous coat of the large 

 intestine. The pouches are covered by the perito- 

 neum and are usually distended with fat. These 

 external features 

 are the surgeon's 

 guide in recogniz- 

 ing the large intes- 

 tine. Size is a less 

 reliable factor. 



Structurally the 

 large intestine has 

 the same four lay- 

 ers as the small in- 

 testine. The three 

 outer layers are 

 identical. The 

 mucosa presents a 

 smooth surface 

 with numerous mi- 

 nute circular pits, 



Fig. 150. Cross section of large intes- 

 tine, showing many goblet cells in epithe- 

 lium. 



the crypts of Lie- 

 berkuhn. As villi 

 are absent the mu- 

 cosa resembles that of the stomach rather than that of 

 the small intestine. The crypts of the stomach are 

 shallow, while those of the intestine are deep and 

 extend to the muscularis mucosa. Each crypt is 

 lined by simple columnar epithelium. Goblet cells 

 are very numerous in this epithelium. 



