IHE ABDOMEN 



793 



Bloodosupply — Arteries. — The duodenum receives its arteries from 

 the superior pancreatico-duodenal of the gastro- duodenal from 

 the hepatic, and the inferior pancreatico- 

 duodenal of the superior mesenteric. The 

 jejimum receives its arteries from the rami 

 intestini tenuis of the superior mesenteric. 

 The ileum also receives its arteries from the 

 rami intestini tenuis, and its terminal part in 

 addition receives its arterial supply from the 

 ileal branch of the ileo-colic from the superior 

 mesenteric. 



Veins. — The destination of the venous blood 

 of the small intestine is the superior mesenteric 

 vein, and thereafter the vena portae. The 

 veins are provided with valves which are 

 competent in early life, but in the adult they 

 are incompetent, and therefore allow regurgi- 

 tation of blood to take place towards the 

 small intestine, as happens in cases of portal 

 obstruction. 



Lymphatics. — ^These form a copious plexus 

 of valved vessels, which is situated in the fig. 341.— A Peyer's 

 submucous coat. This plexus receives the Patch. 



lymphatics of the mucous membrane and the 

 lacteals of the villi, and it surrounds the deep ends of the 

 solitary glands. Its efferent vessels pierce the muscular coat, and 

 in doing so they take up the l^onph from an intramuscular plexus 

 of lymphatics, which lies between the longitudinal and circular 

 layers. They then leave the bowel at the mesenteric border, where 

 they pass between the two layers of the mesentery, and on their 

 way to the receptaculum chyli they traverse the superior mesenteric 

 glands. 



Nerves. — ^These are derived fiom the superior mesenteric sympa- 

 thetic plexus, and they form two gangliated plexuses of non- 

 medullated nerve-fibres. One of these is situated in the muscular 

 coat between the longitudinal and circular layers, and is known as 

 the plexus myentericus of Auerbach (plexus of the muscular coat of 

 the intestine). The other is situated in the submucous coat, and 

 is called the plexus of Meissner. The branches of this latter plexus 

 are distributed to the muscularis mucosae and the mucous membrane 

 with its villi. 



Characters of Different Parts of the Small Intestine — Duodenum— Pcm- 

 tonetim. — There is no mesentery and only a partial investment of peritoneum. 

 Muscular Coat. — This is very thick. Submucous Coat. — This contains the 

 tubular portions of Brunner's glands. Mucous Coat. — The characters of 

 this coat are as follows : ( i ) valvulae conniventes. except in the first i or 

 2 inches, (2) villi, (3) Lieberkiihn's cr^'pts. (4) solitary glands. (5) ducts of 

 Brunner's glands, (6) common orifice of the ductus communis choledochus and 

 pancreatic duct, and (7) orifice of the accessory pancreatic duct, or duct of 

 Santorini. 



