404 



TEXT-BOOK OF PHYSIOLOGY. 



S Trabeculae of 

 hepatic cells. 



.* Central vein. 



structures of the liver, and hence are in close relation with capillary 

 blood-vessels, lymphatic spaces, nerves, and irregular channels or 

 passageways. The latter running between the epithelial cells may 

 be compared to the lumen of other secreting glands. 



Blood-vessels and Their Distribution. The blood-vessels 

 which are in relation with the liver are : 



1. The portal vein. 



2. The hepatic artery. 



3. The hepatic vein. 



The portaj^ydn_and. the. hepatic artery enter the liver at the trans- 

 verse fissure. After penetrating its substance they divide and sub- 

 divide into smaller and smaller 

 branches, which ultimately oc- 

 cupy the space between the 

 lobules, completely surrounding 

 and limiting them. From their 

 situation they are termed inter- 

 lobular veins and arteries. 



The interlobular veins give off 

 small capillary vessels which 

 penetrate the lobule at all points 

 of its surface. These capillaries, 

 though frequently anastomosing, 

 form a radial meshwork which 

 converges toward the center of 

 the lobule. In the meshes of 

 this plexus are found, arranged 

 in a corresponding radial man- 

 ner, the liver cells. The inter- 

 lobular arteries are distributed to 

 the walls of the portal vein, to 

 the connective tissue, and finally 

 terminate in the portal vein capil- 

 laries. The intralobular capil- 

 laries thus receive and transmit 

 1 which is an admixture of both arterial and venous blood. In 

 the center^feacMobuleJhere is a large vein, formed by the union of 

 the intralobular c^1^nes^n6wn~^t^intralobular vein, which 

 Elects afl Jheblood of the lobule and transmits it through the lobule 

 .o an underlying or sublobular vein (Fig. 1 86). These latter vessels, 

 I!? S g ^ reunitin S> ultimately form the hepatic vein, wMfihempties 

 the blood into the inferior vena cavaT" 



Bile Capillaries and Hepatic Ducts.-The bile capillaries are 

 row channels which penetrate the lobule in all directions and are 

 erally found running along the sides of the cells. These channels, 



Interlobular vein. Hepatic duct. 



FIG. 185. SCHEME OF A HEPATIC LOB- 

 ULE, REPRESENTED IN TRANSVERSE 



SECTION BELOW AND, BY PARTIAL 

 LEVELING, IN LONGITUDINAL SEC- 

 TION ABOVE. In the left half the 

 blood-vessels are drawn; in the right 

 half only the cords of hepatic cells. 

 X 20. (Stohr.} 



