274 /j, ' HANDBOOK OF PHYSIOLOGY: 



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THE LIVER. 



The Liver, the largest gland in the body, situated in the abdomen on 

 the right side chiefly, is an extremely vascular organ, and receives its sup- 

 ply of blood from two distinct sources, viz., from the portal vein and from 

 the hepatic artery, while the blood is returned from it into the vena cava 

 inferior by the hepatic veins. Its secretion, 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 

 veins and their 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 



Fio. 204. The under surface of the liver, o. B., gall-bladder; H. D., common bile-duct; H. A., 

 hepatic artery; v. p., portal vein; L. Q., lobulus quadratus; L. s., lobulus spigelii; L. c., lobulus 

 caudatus; D. v., ductus venosus; u. v., umbilical vein. (Noble Smith.) 



whole surface of the organ. It is thickest when the peritoneum is ab- 

 sent, and is continuous 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 invest^ 

 ment called Glisson's capsule, which, surrounding the portal vein, he- 

 patic artery, and hepatic duct, as they enter at this part, accompanies 

 them in their branchings through the substance of the liver. 



Structure. The liver is made up of small roundish or oval portions 

 called lobules, each of which is about -fa of an inch in diameter, and 

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

 patic duct, and hepatic vein; while the interstices of these vessels are 

 filled by the liver cells. The hepatic cells (Fig. 205), which form the 

 glandular or secreting part of the liver, are of a spheroidal form, some- 

 what polygonal from mutual pressure, about -g-Jo-to y^-g-inch in diameter, 

 possessing one, sometimes two nuclei. The cell-substance contains nu- 



