NERVE SUPPLY 297 



distributes its branches to the capillaries about the crypts of 

 Lieberkuhn and to the intestinal villi. 



The artery of the villus enters at its base, and, distributing 

 capillaries along its course, forms in the distal part of the villus 

 an abundant capillary network from which efferent venules return 

 by a similar course. The artery, however, is found near the axis, 

 the venules near the periphery of the villus. 



Branches from the submucous and mucous arterial plexuses 

 also supply capillaries to the glands of Brunner in the duodenum 

 as well as to the solitary and agminated lymphatic follicles. About 

 each of the lymphatic nodules they form circular anastomoses 

 from which radial capillaries are distributed within the follicle. 



The veins pursue a course exactly similar to that of the arteries. 

 On their way to the mesenteric vessels they form mucous, submu- 

 cous, intramuscular, and subserous plexuses. 



LYMPHATICS. The lymphatics or lacteals of the small intes- 

 tine begin in the distal part of the villi as lymphatic capillaries, each 

 having, as a rule, a pouched, blind extremity. At their origin the 

 lacteals are frequently branched, or they may even form a scanty 

 anastomosis. They finally unite to form a central lacteal in the 

 axis of the villus, which empties into a rich plexus about the 

 crypts of Lieberkuhn, or, like the efferent vessels of this plexus, 

 they may pass directly to the larger lymphatic vessels of the 

 submucosa. 



From the submucous plexus numerous efferent lymphatic ves- 

 sels penetrate the muscular coat, receiving the lymph from the 

 vessels of the intramuscular septum. They empty into the larger 

 lacteal vessels of the mesentery which are intimately connected 

 with numerous mesenteric lymphatic glands. In the mucosa and 

 submucosa the lacteals form sinuses which surround the bases of 

 the nodules of the solitary and agminated follicles. Thus, much of 

 the chyle is permitted to come into relation with the parenchyma 

 of these organs before leaving the intestinal mucosa. 



NERVE SUPPLY. The nerve supply of the intestine is ex- 

 actly similar to that of the stomach. The non-medullated fibres 

 form an intramuscular ganglionic plexus (Auerbach's) for the 

 supply of the muscular coat, and a submucous.plexus (Meissner's) 

 which supplies branches to the blood vessels and to the glands of 

 the mucosa. The finer branches in the mucous membrane pene- 

 trate to the villi, forming a delicate plexus of naked fibrils about 

 its blood vessels and lacteals, and beneath its epithelium, 



