SYSTEM. 



197 



lymph they contain after each meal. The villi de- 

 velop as invaginations of the mucosa and are exclu- 

 sively confined to the small intestine. 



(c) Crypts of Lieberkuhn. These are sometimes 

 spoken of as intestinal glands. They consist of pits 

 or evaginated diverticulce of the mucous epithelium 

 that open as pores between the bases of the villi. 

 The bottom of these crypts rests against the muscu- 

 laris mucosa. Goblet cells are particularly numer- 

 ous in the epithelial lining of their walls. Crypts 



-Central 

 chyle-vessel 

 of villas. 



.yle-vessel. 



Artery. 



-Mucosa. 

 l-Muscularis 

 mucosse. 

 -Submucosa. 



Plexus of 

 ' lymph-ves- 

 sels. 



. Circular mus- 

 ~~ cular layer. 



Plexus of 

 ., lymph-ves- 

 .%% sels. 

 .-.>": V~. 7 " Long, muse. 



" layer with 



serous coat. 



Fig. 146. Schematic transverse section of the human small intestine 

 (after F. P. Mall). 



are also present in the large intestine and are analo- 

 gous to the shorter crypts of the stomach into which 

 the gastric glands open. 



Snlitarv T.vm<hk Nodules. These are simple nodes 



