1718 



HUMAN ANATOMY. 



surface of the lobule. They consist of a dense fibro-elastic coat lined with cylindri- 

 cal epithelium, some .020 mm. thick, which latter is continued into the low cuboidal 

 or flattened cells that form the lining of the excretory channels connecting the intra- 

 lobular net-work of bile-capillaries with the bile-ducts. Beginning as the small 

 vessels that surround the lobules, they become tributary to the larger bile-ducts, 

 which increase in diameter as they approach the transverse fissure. In the vicinity 

 of the latter these trunks join into the two main lobular ducts forming the hepatic 

 duct. The largest bile-vessels possess bundles of unstriped muscle which in the 

 hepatic duct are arranged principally as a longitudinal layer, supplemented by cir- 

 cular and oblique bundles (Hendrickson). 



Gall-bladder 



THE BILIARY APPARATUS. 



In addition to the small interlobular bile-vessels already described, the system 

 of canals receiving and conveying the secretion of the liver to the intestinal tract 

 consists of the hepatic dud, the excretory tube of the organ ; the gall-bladder, a res- 

 ervoir in which the bile ac- 



FIG. 1452. cumulates during intervals 



of digestion; the cystic duct, 

 the continuation of the bile- 

 sac opening into the side of 

 the hepatic duct ; and the 

 common bile-duct, which, al- 

 though formed by the union 

 of the other two, is in struc- 

 ture and direction really the 

 continuation of the hepatic 

 duct. 



The hepatic duct (duc- 

 tus hcpaticus) is formed be- 

 low the hilum by the union 

 of its two a right and a 

 left chief tributaries. The 

 latter issue from the portal 

 fissure, one on each side, 

 and generally urrite with the 

 hepatic duct nearly in the 

 shape of a T, the last-named 

 canal forming almost a right 

 angle with each of its tribu- 

 taries. Tracing the chief 

 ducts into the liver, the left 

 branch runs at first in front 

 of the left division of the 

 portal vein, while the right 

 one usually crosses it. We 

 have seen the hepatic duct 

 issue from the right lobe 

 and, forming a loop in the 

 fissure, leave it with the left 

 division of the portal vein, 

 receiving branches along its 

 convexity from the various parts of the liver. Sometimes the chief ducts are longer 

 than usual, and meet to form the hepatic duct at an acute angle farther from the 

 liver. The length of the hepatic duct, therefore, varies with these details, proba- 

 bly beiu^ usually from 20-40 mm. (^-l^ in.), with a diameter of from 4-6 mm. 

 It lies in the gastro-hepatic omentum, in front of the portal vein and to the right 

 of the hepatic artery, and inclines downward to the inner side of the second part 

 of the duodenum, resting previously on the top of the first part. The hepatic duct 



Vena cava 



Probe in for. mien 

 of Winslow 



Ik-patio 

 artery 



Common 



bilr-diiet 



duct 



Hepatic duct 

 Cystic duct 



Common bile-duct 



ital vein 



Head of 



pancreas 

 turned back 



Superior 

 / mesenteric 

 I \rin 

 J-Superior. 



mesiMiteric 



artery 



Portions of liver, duodenum, ami pain 

 ducts 



sbmvini; biliary and pancreatic 

 head <>l pain-iras timuM back. 



