OH. XXVII.] 



INTESTINAL GLANDS. 



451 



Glamls. The glands are of two kinds : viz., those of Lieber- 

 kiihn and of Brunner. Peyer's patches and the solitary follicles 

 are composed of lymphoid nodules. Though sometimes called 

 glands, they form no external secretion. 



The glamls or crypts of Lieberkiihn are tubular depressions 

 of the intestinal mucous membrane, thickly distributed over 

 the whole surface both of the large and small intestines. In 

 the small intestine they are visible only with the aid of a lens ; 

 and their orifices appear as minute dots scattered between the 

 villi. They are larger in the large intestine, and increase in size 



Fig. 384. Transverse section through 

 four crypts of Lieberkiihn from the 

 large intestine of the pig. They are 

 lined by columnar epithelial cells, the 

 nuclei being placed in the outer part 

 of the cells. The divisions between 

 the cells are seen as lines radiating 

 from L, the lumen of the crypt; o, 

 epithelial cells, which have become 

 tranxf ormed into goblet cells, x 350. 

 (Klein and Noble Smith.) 



Fig. 385. A gland 

 of Laeberkiihn in 

 longitudinal sec- 

 tion. (Brinton.) 



the nearer they approach the anal end of the Intestinal tube ; 

 and in the rectum their orifices may be visible to the naked eye. 

 In length they vary from T | 7r to ^ of an inch. Each tubule 

 (fig. 385) is constructed of a fine basement membrane, lined by a 

 layer of columnar epithelium, many of the cells of which are 

 goblet cells. 



Srunnei-'s glands (fig. 381) are confined to the duodenum; they 

 are most abundant and thickly set at its commencement, and 

 diminish gradually as the duodenum advances. They are situated 

 beneath the ir.uscularis mucosae, imbedded in the submucous 

 tissue ; each gland is a branched and convoluted tube, lined with 

 columnar epithelium. In structure they are very similar to the 

 pyloric glands of the stomach, but they are more branched and 

 convoluted and their ducts are longer. The duct of each gland 



o o 2 



