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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. 



Lymph- 

 nodule. 



----%-- Muscularis 

 mucosae. 



Pyloric 

 glands. 



Brunner's 

 glands. 



Villus. 



1&~ 



JJI-?'~'~ Muscularis mucosae. 



m 



"- Submucosa. 



Villus. 



Brunner's glands. 



' ptP> \Blood-vessel. 



''-Glands of Lieberkuhn. 



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

 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 



