VESSELS AND DUCT OF LIVER. 



471 



From the arrangement of the vessels, it appears that the portal vein 

 conducts the blood from which bile is secreted ; that the hepatic vein car- 

 ries away the superfluous blood; and that the secreted bile is received by 

 the plexus of the biliary duct. 



VESSELS OF THE LIVER. Two sets of bloodvessels ramify in the liver : 

 One enters the transverse fissure, and is directed transversely in spaces 

 (portal canals) where it is enveloped by areolar tissue. The other set 

 (hepatic veins) run from the anterior to the posterior border of the liver 

 without a like sheath. The ramifications of these different vessels are to 

 be followed in the liver. 



The capsule of Glisson is a layer of areolar tissue, which envelops the 

 vessels and the ducts in the transverse fissure. In this sheath the vessels 

 ramify, and in it they are minutely divided before their termination in 

 the lobules. If a transverse section is made of a portal canal, the vessels 

 will retract somewhat into the loose surrounding tissue. 



The vena portce ramifies in the liver like an artery ; and the blood cir- 

 culates through it in the same manner, viz., from trunk to branches. After 

 entering the transverse fissure the vein divides into large branches ; these 

 lie in the portal canals or spaces, with offsets of the hepatic artery, the 

 hepatic duct, and the nerves and lym- 

 phatics (fig. 161, P). The division is 

 repeated again and again until the last 

 branches of the vein (interlobular, fig. 

 1 60, b~) penetrate between the lobules ; 

 there they unite, and end in the interior 

 as before explained. 



In the portal canals the offsets of the 

 vena portcp are joined by small vagi- 

 nal and surface veins, which convey 

 blood from branches of the hepatic 

 artery. 



The hepatic artery (fig. 161, c), 

 whilst surrounded by the capsule, fur- 

 nishes vaginal branches, which ramify 

 in the sheath, giving it a red appear- 

 ance in a well-injected liver, and sup- 

 ply twigs to the coats of the vena 

 portje and biliary ducts, and to the areo- 

 lar tissue: from the vaginal branches a 

 few offsets (capsidar} are given to the 

 coat of the liver. Finally the artery 

 ends in fine interlobular branches, from 

 which offsets enter the lobule, and con- 

 vey blood into the network between the 

 brandies of the vena portre and hepatic 

 vein (Chrzonszczewsky). 



The hepatic vein (venae cavrc hepaticne) begins by a plexus in the inte- 

 rior of each lobule (fig. 160, c?), and its smallest radicle issues from 

 the base of the lobule as the intralobular vein ; these are received into 

 the sublobular branches, which anastomose together, and unite into larger 

 vessels. Finally, uniting with neighboring branches to produce larger 

 trunks, the hepatic veins are directed from before backwards to the vena 

 cava inferior, into which they open by large orifices. The vena3 cavas he- 



IN A PORTAL CANAL, AND THE 

 LOBULKS OF THE LIVER (Kieriiau). 

 I. Lobules of the liver. 

 P. Branch of the veua portae, with, a, a , 

 vaginal branches which supply inter- 

 lobular offsets. 



c. Hepatic artery. 



d. Hepatic duct. 



i, i. Openings of the interlobular branches 

 of the portal vein. 



