THE LIVER 1187 



Various Forms of Duodenum. Three different types of duodenum have been described 

 (1) The annular, in which the curves separating the various parts are open, and the two 

 extremities come fairly close to one another. (2) The U-shaped, in which the horizontal part of 

 the inferior part is very long, and the ascending part is nearly vertical; and (3) the V-shaped 

 duodenum, in which the horizontal portion of the inferior part is very short or absent. 



Vessels and Nerves. The duodenum receives its blood from the superior and inferior 

 pancreatico-duodenal arteries, branches of the gastro -duodenal and superior meseriteric arteries 

 respectively. The blood is returned by the corresponding veins, the superior of which opens into 

 the superior mesenteric, and the inferior into the beginning of the portal vein. 



The lymph vessels of the duodenum follow for the most part the course of the blood-vessels. 



From the anterior surface, lymph vessels pass along the course of the inferior pancreatico- 

 duodenal artery, and communicate with lymph glands found along the course of that vessel. 

 Thence they pass to the inferior cceliac glands, beside the origin of the superior mesenteric artery. 



The vessels from the posterior aspect accompany the superior pancreatico-duodenal artery, 

 communicate with the inferior gastric glands, and terminate in the cceliac glands. 



The nerves come from the cceliac plexus of the sympathetic. 



Flexura Duodenojejunalis. When the ascending part of the duodenum 

 reaches the inferior surface of the pancreas, at a point opposite the left side of 

 the first or second lumbar vertebra, it turns abruptly forwards, downwards, and 

 to the left, and passes into the jejunum. This abrupt bend is known as the 

 duodeno-jejunal flexure. Unlike the rest of the duodenum, which is subject to 

 considerable variations in position in different individuals, the duodeno-jejunal 

 flexure is fixed by a thin band of unstriped muscle, which is attached above to the 

 strong connective tissue around the cceliac artery, as well as to the left crus of the 

 diaphragm. This band passes posterior to the pancreas, and inferiorly it joins the 

 muscular coat of the duodenum at the flexure. It is known as the m. suspensorius 

 duodeni (O.T. muscle of Treitz). 



The duodeno-jejunal flexure is occasionally directed to the right, and it lies at 

 a variable distance from the root of the transverse mesocolon. When the attach- 

 ment of the transverse mesocolon is low, the duodeno-jejunal flexure is in contact 

 with it. 



Duodenal Pouches or Diverticula. Occasional diverticula are found passing from the 

 duodenal wall in different directions. Such diverticula may be hernial protrusions of the 

 mucous and submucous coats through the muscular wall, termed false diverticula, or they may 

 be " true " diverticula, in which all the coats are represented. 



They are usually situated on the aspect of the duodenum which is in contact with the pancreas, 

 and frequently in the neighbourhood of the orifice of the bile duct. 



Some of these appear to be due to the pressure from the interior of the duodenum, while 

 others, and the majority of the true diverticula, are rather congenital in origin, and are 

 possibly associated with the diverticula which give rise to the liver and pancreas. 



HEPAR 



The liver is the large glandular organ which secretes the fluid called bile 

 (fel). It occupies the superior and mainly the right portion of the abdominal cavity, 

 and lies immediately below the diaphragm. 



Its secretion is conveyed away from it by the hepatic ducts and the bile-duct to 

 the duodenum. With the bile duct there is connected a pear-shaped diverticulum, 

 the gall-bladder (vesica fellea), which lies -in contact with the liver, and which 

 serves apparently for the temporary storage of bile. 



In addition to secreting bile, the liver plays an important part in the 

 metabolism of both the carbohydrate and nitrogenous materials absorbed from the 

 intestine which are conveyed to it by the portal vein, and it also has to do with 

 the production and the destruction of some of the blood-cells. 



Physical Characters. The liver is a large irregularly shaped mass, of a 

 reddish-brown colour, soft and pliant to the touch, somewhat readily lacerated, and 

 highly vascular. 



It is of uniform consistence throughout, and little of its internal structure can 

 be made out by naked-eye examination. If, however, a torn surface is examined, 

 the liver tissue is seen to be somewhat granular. Under the investing peritoneum 

 the surface is somewhat mottled. 



This mottled or granular appearance is due to the lobules (lobuli hepatis) of 



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