THE DIGESTIVE SYSTEM 



315 



adult. The walls of the large intestine are sacculated, and they bear 

 externally numerous fatty appendages, the appendices epiploicae. The 

 longitudinal muscles do not form a continuous layer as in the small 

 intestine, but are arranged in three longitudinal bands, the teniae. Trans- 

 verse crescentic folds, the plicae semilunares, are abundant. Between 

 these the wall of the colon bulges out to form haustra. 



The large intestine is divided into cecum, vermiform appendix, colon, 

 rectum, and anus. The cecum is a bUnd sac, about two and a half inches 



Glands. ? 



Muscularis 

 mucosa. 



Submu- 

 cosa. 



Solitary nodule with germinal center. 

 — Vertical section of the mucous membrane of the descending colon of an 

 adult man. The fat has been blackened with osmic acid. (From Bremer's "Text Book 

 of Histology.") 



Fat cells. 



Fig. 264. 



in length, lying near the ileocolic valve in the right iUac fossa. The 

 vermiform appendix of the cecum is an elongated worm-shaped tube 

 between three and four inches in length, attached to the apex of the cecum. 

 The structure of the appendix is similar to that of the large intestine in 

 having numerous Lieberkuehn's glands and lymph nodules. In the 

 majority of persons, the lumen becomes occluded in later life. The 

 appendix appears to be a rudiment of a more extended cecum functional 

 in the ancestors of man. 



The colon is divided into four regions, ascending, transverse, 

 descending and sigmoid colon. The ascending colon passes up the right 

 side of the abdominal cavity as far as the liver, where it bends to the left 



