390 



BRUNNER'S GLANDS AND SOLITARY FOLLICLES. 



Non-striped muscular fibres are present in villi (Henle). Some are arranged 

 longitudinally from base to apex, immediately outside the central lacteal. When 

 they contract they tend to empty the lacteal (Briicke). A few muscular fibres are 

 placed more superficially, and run in a more transverse direction. [The muscular 

 fibres of the villi are direct prolongations of the muscularis mucosse]. 



Nerves pass into the villi from Meissner's plexus lying in the sub-mucous coat. 

 The nerves to the villi are said to have small granular ganglionic cells in their 

 course, and they terminate partly in the muscular fibres and partly in the arteries 

 of the villi. 



[On making a vertical section of the muCOUS membrane of the small intestine, 

 it is seen to consist of a net-work of adenoid tissue loaded with leucocytes. This 

 tissiie forms its basis, and in it are placed vertically side by side, like test-tubes in 

 a stand, immense numbers of simple tubular glands the Crypts of Lieberkllhn 

 (Fig. 151). They open above at the bases of the villi, while their lower extremity 

 reaches almost to the muscularis mucosse. Each tube consists of a basement mem- 

 brane lined by a single layer of columnar epithelium, leaving a wide lumen, the 

 cells lining them being continuous with those that cover the mucous membrane. 

 Some goblet-cells are often found between the columnar epithelium. Immediately 

 below the bases of the follicles of Lieberkuhn is the muscularis mucoste, consisting of 

 two or three narrow layers of non-striped muscular fibres arranged circularly and 

 longitudinally. It is continuous with the muscularis mucosa? of the stomach, aud 

 extends throughout the whole intestine. It sends fibres upwards into the villi.] 



[Brunner's glands are compound tubular glands lying in and confined to the 

 sub-mucous coat of the duodenum. Their ducts perforate the muscularis mucosse 

 to open on the surface. They seem to be the homologues of the pyloric glands of 

 the stomach (p. 308).] 



[Solitary follicles are small round or oval white masses of adenoid tissue, 

 with their deeper parts embedded in the sub-mucosa, and their apices pro- 

 jecting into the mucosa of the intestine. They begin at the pyloric end of the 



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Section of a solitary follicle of the small intestine (human), showing a, lymph- 

 follicle covered with epithelium (b) which has fallen from the villi, c ; d, 

 Lieberkiihn's follicle ; c, muscularis mucosse ; /, sub-mucous tissue. 



