DUCTS OF THE LIVER. 28? 



§ 746. Ductus hepatici — Bile ducts. — Press on the cliolecyst, 

 and the contained Ibile will be forced into the various Mle ducts : — 



(1) Ductus cysticus. — This is the duct extending from the smaU 

 end of the cholecystis to the ductus communis (3). It presents sev- 

 eral loops, the so called impeding flexures, and serves to conduct 

 the bile to or from the cholecyst (Pig. 79, 81, 82). 



(2) Ductus Jiepatici (Pig. 79). — These are the bile ducts proper. 

 They convey the bile from the various lobes of the liver to the duc- 

 tus communis (Pig. 79, 81). Press on the cholecystis again if neces- 

 sary to make them evident. Isolate one by means of the tracer. 

 Cut a V-shaped slit in it near its end and press all of the bile in the 

 cholecyst out through the slit. Then insert a canula through this 

 slit and inject toward the cholecyst with plaster (§ 359). This will 

 fill all the ducts as well as the cholecyst, and after the plaster has 

 set they may be traced in the same way as ai-teries, (§ 596 [10]). 



(3) Ductus cTioledocTius communis — The common bile duct. — 

 As the name implies, this receives aU of the other ducts from the 

 liver. It appears to be a continuation of the cystic duct. It reaches 

 the duodenum about 8 cm. from the pylorus, and enters it obliquely 

 caudad. Within the walls of the duodenum, it empties into a small 

 reservoir {ampulla of Yater), common to it and the duct of Wir- 

 sung (Pig. 84). 



The character of the opening of the ductus choledochus and its 

 relation to the ductus Wirsungianus are shown in Pig. 84. 



§ 747. Obvious Structure oftTie Liver (hepar). — (A) Lobi. — The liver is composed of sev- 

 eral deep red lobes, which are smooth and shining on the surface from the presence of the 

 peritoneal investment. This is very thin an'd is separated with diflaculty, even over small 

 areas. 



(B) Lohuli — Lobules. — These are plainly visible as small areas about 1 mm. in diam- 

 eter, surrounded by rings of deeper color. 



(C) Parenchyma. — If a piece is cut out, it may be readily crushed into a pasty mass, 

 showing that the structure is pulpy and cellular rather than fibrous. 



§ 748. Microscopic Structure. — (A) Peritoneal or serous coat. (B) Fibrous coat (pro- 

 jections of this accompany the vessels). (C) Liver substance ; this consists of lobules 

 composed of polyhedral cells arranged in a radiate manner around the center of the lobule. 



Vessels of the Lobule. — (1) Intralobular vein or hepatic veinlet in the center of the lob- 

 ule ; (2) Interlobular or portal veinlet and the hepatic arteriole. These are between the 

 lobules, and capillaries pass from them to the center of the lobule between the rows of 

 hepatic cells. In addition to the above, are the beginnings of the hepatic ducts. See 

 Strieker, A, 407 ; Quain, A, II, 386. 



' § 749. Pancreas, az. (Pig. 81, § 720). — The cat's pancreas is 

 greatly elongated, and so bent as to form two sides of a triangle. 



