THE LIVER. 



1061 



branches of the hepatic artery (Fig. 670). Thus it will be seen that all the 

 blood carried to the liver by the portal vein and hepatic artery, except perhaps 

 that derived from the interlobular branches of the hepatic artery, directly or 

 indirectly finds its way into the interlobular plexus. From this plexus the blood 

 is carried into the lobule by fine branches which pierce its wall and then converge 

 from the circumference to the centre of the lobule, forming a number of longitu- 

 dinal vessels which are connected by transverse or horizontal branches (Fig. 671). 

 In the interstices of the network of vessels thus formed are situated, as before 

 said, the liver-cells : and here it is that, the blood being brought into intimate 

 connection with the liver-cells, the bile is secreted. Arrived at the centre of the 

 lobule, all these minute vessels empty themselves into one vein, of considerable 

 size, which runs down the centre of the lobules from apex to base and is called 

 the intral'-ibular vein. At the base of the lobule this vein opens directly into the 

 sublobular .'-in. with which the lobule is connected, and which, as before men- 



FIG. 672. Origin of the hepatic veins. (Sappey.) 1. Sublobular vein. 2, 2. Intralobular veins. 3, 3. Trib- 

 utaries to 2. 4. 4. Capillary network between portal and hepatic systems. 



tioned, is a radicle of the hepatic vein (Fig. 672). The sublobular veins, uniting 



into larger and larger trunks, end at last 

 in the hepatic veins, which do not receive 

 any intralobular veins. Finally, the he- 

 patic veins, as mentioned at page 1057, 



Biliary .^-N 



" duct. 



Hepatic 

 cells. 



Capillary. 



Biliary duct. 



FIG. 673. Section of liver. 



Fig. 674. A transverse section of a small portal 

 canal and its vessels. (After Kiernan.) L Portal vein. 

 2. Interlobular branches. 3. Vaginal branches. 4. 

 Hepatic duct. 5. Hepatic artery. 



converge to form three large trunks which open into the inferior vena cava, while 

 that vessel is situated in the fissure appropriated to it at the back of the liver. 



