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TEXT-BOOK OF PHYSIOLOGY. 



1. The portal vein. 



2. The hepatic artery. 



3. The hepatic vein. 



The portal vein and the hepatic artery enter the liver at the transverse 

 fissure. After penetrating its substance they divide and subdivide into 

 smaller and smaller branches, which ulimately occupy the space between the 

 lobules, completely surrounding and limiting them. From their situation they 

 are termed interlobular 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 corres- 

 ponding radial manner, the liver cells. The interlobular arteries are distrib- 

 uted to the walls of the portal vein, to the connective tissue, and finally 

 terminate in the portal vein capillaries. The intralobular capillaries thus 

 receive and transmit blood which is an admixture of both arterial and venous 





FIG. 209. TRANSVERSE SECTION OF A SINGLE HEPATIC LOBULE, i. Intralobular vein, cut 

 across. 2, 2, 2, 2. Afferent branches of the intralobular vein. 3,3,3,3,3,3,3,3,3. Interlobular 

 branches of the portal vein, with its capillary branches, forming the lobular plexus, extending to 

 the radicles of the intralobular vein. (Sappey.) 



blood. In the center of each lobule there is a large vein, formed by the union 

 of the intralobular capillaries, known as the intralobular vein, which collects 

 all the blood of the lobule and transmits it through the lobule to an underly- 

 ing or sublobular vein (Fig. 209) . These latter vessels, uniting and reuniting, 

 ultimately form the hepatic vein, which empties the blood into the inferior 

 vena cava. 



Bile Capillaries and Hepatic Ducts. The bile capillaries are narrow 

 channels which penetrate the lobule in all directions and are generally found 

 running along the sides of the cells. These channels, which are devoid of 

 walls, receive from the cells some of the products of their secretor activity, 

 and hence are comparable to the lumen of the alveoli of other secreting 

 glands. At the periphery of the lobules the bile capillaries communicate 

 with larger channels which are the beginnings of the hepatic or bile-ducts 



