278 



THE DIGESTIVE ORGANS. 



forms. The mucosa is separated from the glands, from the 

 epithelium of the villi, as well as from that of the remain- 

 ing surface of the intestine by a peculiar basement membrane. 



Longitudinal 

 , muscular 

 layer. 



Sphincter '' 

 pylori. 



Submucosa. 



Muscu'aris 

 mucosae. 



Pyloric 

 glands. 



Brunner's 

 glands. 



' Lymph- Villus. 



nodule. 



- a 



Longitudinal 

 muscular 

 layer. 



Circular mus- 

 cular layer. 



Hr~"~ Muscularis mucosae, 



^lb 



??-5 ~" Submucosa. 

 ""~ Villus. 



' 



Brunner's glands. 



\Blood-vessel. 



''-Glands of Lieberkiihn. 



Fig. 218. Section through the junction of the human pylorus and duodenum ; 

 15 : At a the pyloric glands extend into the duodenum. 



The latter somewhat complicates a proper histologic analysis, and 

 as a consequence opinions regarding its structure and significance 

 vary considerably. By some it has been described as a homo- 

 geneous, hyaline, and exceedingly fine membrane containing nuclei, 

 by others as a lamella consisting entirely of endothelial cells. At 

 all events, there are certainly nuclei in the basement membrane. 

 Beneath the basement membrane is a marginal layer of a more 

 fibrillar character. This is closely associated with the mucosa, and 



