200 



STRUCTURE OF THE LIVER. 



Fig. 85. 



Origin of hepatic veins in the liver lobules. 



ted ; the hepatic artery brings aerated Wood for the nourishment of the 

 gland ; the bile-ducts carry away the biliary secretion which has been 

 separated from the portal blood, and the residue, taken charge of by the 

 hepatic veins, is eventually carried back into the general circulation 

 through the vena cava. 



A general idea of the mode of arrangement of the four vessels in the 



liver may be obtained by recalling 

 the illustration just given, that the 

 lobules are placed on the commence- 

 ment of the hepatic veins, like grapes 

 on their stalks. The vein originates 

 in the centre of each lobule, as shown 

 at a a, in Fig. 85, and exhibits there 

 a ray-like kind of divergence. On 

 the periphery of each lobule, at #, 5, #, 

 as it were on the surface of the 

 grape, the other three vessels ram- 

 ify. Of them the portal veinlets dip 

 down into the substance of the lob- 

 ule. The hepatic arteries likewise 

 enter for the purpose of giving nutri- 

 tion to the parts. In Fig. 86, #, a are the commencing hepatic or intra- 



lobular veins of two lobules ; , #, 

 the biliary ducts ; c, interlobular 

 tissue ; d d, parenchyma of the lob- 

 ules. With respect to the bile- 

 ducts, which are prominently rep- 

 resented in this figure, it is not pos- 

 itively known whether they pro- 

 ceed beyond the surface, and the 

 manner in which they are related 

 to the secreting cells, and receive 

 the liquid yielded by them, is a sub- 

 ject of controversy. The inter- 

 spaces between the capillaries that have entered the lobules are filled up 

 with these cells. 



It is not known whether the hepatic artery discharges its blood into 



He atic cells ^ P orta ^ capillaries, or into those of the hepatic vein, and, 



for this reason, it is doubtful whether that blood takes part 



in the secretion of the bile. The secreting cells have nucleolated nuclei, 



and are about the - 2 * 6 of an inch in diameter. 



In Fig. 87, at <z, #, #, their normal state is shown. They are filled 

 with a yellowish, granular soft substance ; at b b is the appearance of fat 



I T> 



Origin of bile-ducts on the liver lobules. 



