STRUCTURE OF THE LIVER. 321 



Structure of the Liver. 



The liver is an extremely vascular organ, and receives 

 its supply of blood from two distinct vessels, the portal 

 vein and hepatic artery, while the blood is returned from it 

 into the vena cava inferior by the hepatic vein. Its secre- 

 tion, the bile, is conveyed from it by the hepatic duct, either 

 directly into the intestine, or, when digestion is not going 

 on, into the cystic duct, and thence into the gall-bladder, 

 where it accumulates until required. The portal vein, 

 hepatic artery and hepatic duct branch together throughout 

 the liver, while the hepatic vein and its tributaries run by 

 themselves. 



On the outside the liver has an incomplete covering of 

 peritoneum, and beneath this is a very fine coat of areolar 

 tissue, continuous over the whole surface of the organ. 

 It is thickest where the peritoneum is absent, and is con- 

 tinuous on the general surface of the liver with the fine, 

 and in the human subject, almost imperceptible, areolar 

 tissue investing the lobules. At the transverse fissure it is 

 merged in the areolar investment called Glisson's capsule, 

 which, surrounding the portal vein, hepatic artery and 

 hepatic duct, as they enter at Fig. 82, 



this part, accompanies them 

 in their branchings through 

 the substance of the liver. 



The liver is made up of 

 small roundish or oval por- 

 tions called lobules, each of 

 which is about -^ of an inch 

 in diameter, and composed of 



the minute branches of the- portal vein, hepatic artery, 

 hepatic duct, and hepatic vein; while the interstices of 

 these vessels are filled by the liver cells. These cells 

 (fig. 82) which make up. a great portion of the substance 

 of the organ, are rounded or polygonal from abo-ut -g^ to 



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