THE VISCERA. 211 



turn ; the descending and inferior portions are only covered by it in front, 

 their posterior surface being attached by uniting tissue to the parts lying be- 

 hind. The Duodenum is therefore little moveable. 



Vessels : Jlrt. and Ven. gastro-duodenalis (from the Hepaticd) for the superior 

 portion, JLrt. mesenterica super, for the inferior. Lymphatics : they pass into 

 the glands above the Pancreas. 



Nerves : they come from Pkx. axliacus and hepatic. 



Function of the Duodenum : the metamorphosis of the Chyme into Chyk by 

 the bile and the succus pancreaticus. 



440. b. The Jejunum (the empty) and fleum (the convo- 

 luted) mesenteric intestine, the most moveable, attached by a fold 

 of peritonaeum (mesenterium) to the vertebral column and the 

 longest portion of the small intestine, passes from the termination 

 of the duodenum at first backwards and forwards and from right 

 to left, winds in many convolutions (gyri) through the reg. umbi- 

 licalis and hypogastrica into the small pelvis, whence it ascends, 

 lying between rectum and bladder, transversely from left to right, 

 and (before m. psoas), to enter vertically the large intestine. 

 Commencement: to the left of the second lumbar vertebra; 

 termination : in the fossa iliaca dextra. The interval between 

 the two points being four inches in length. The length of the 

 mesenteric intestine measures nineteen feet; the width in the 

 superior part = 6 4 inches, in the centre = 4 2, at the terminal 

 portion = 3 5, and at the termination itself = 4 5. The greater 

 the width the more deficient in length. Shape : cylindrical. To 

 the posterior concave border the mesenterium is attached. The 

 anterior convex border is separated from the abdominal parietes 

 by the great omentum. Each convolution is almost entirely 

 circular. It is not uncommon to find at the inferior part of the 

 mesenteric intestines finger-shaped appendages (diverticula), two 

 to three inches long, which occasion hernias (hernias Littricse). 



Structure, a. The mucous membrane is distinguished by : 



1. Valv. conniventes Kerk. 



2. Glandul. Peyeriana, on the anterior intestinal wall. 



3. Valvula Bauhini s. Fallopia s. Tulpii s. Ileo-ctecal consists of a fold of 

 mucous membrane which projects into the large intestine at the termination 

 of the small, becomes reflected, and passes over upon the caecum. Between 

 the two layers of the fold (valve) he circular muscular fibres. The ends of 

 the valve are called Frenula Morgagni. 



[Another fold projects towards the colon, V. Heo-colic.'] 



b. The muscular coat is thinner at the commencement than farther down. 



c. The serous coat (Peritonaeum) completely covers the mesenteric intes- 

 tine, except a small stripe at the part to which the two layers of the mesen- 

 tery are attached. 



Vessels : Jlrt . intestinales from the a. mesenterica super. ; Veins : they open 

 in the V. mesenterica major (branch of Ven. portte"j the Lymphatics are the 

 Lacteals, and go into the glands of the mesentery. 



Nerves : from plexus mesentericus. 



Function of the mesenteric intestine : absorption of the Chyle. 



