CHAPTER LIV 

 THE FUNCTIONS OF THE LIVER AND SPLEEN 



THE liver is developed as a tubular outgrowth from the duodenum. 

 The ultimate endings of this tube break up into numerous fine ducts 

 lined by epithelial cells of large size the liver cells. The whole 

 makes a lobulated gland, the lobule belonging to each branching 

 duct being separated from its neighbour by connective tissue 

 (Glisson's capsule). In this interlobular connective tissue run 

 (1) bile ducts, (2) branches of the portal vein (interlobular), 

 (3) branches of the hepatic artery, (4) lymphatic vessels. In (1) 

 bile, in (4) lymph flows from the lobules, in (2) and (3) blood 

 flows to the lobules. The liver lobule has a large blood-supply. The 

 hepatic artery brings oxygenated blood, and the portal vein blood 

 containing foodstuffs which have been absorbed from the alimentary 

 canal. The capillaries arising from the artery and portal vein anastomose 

 as they radiate through the lobule, forming a network of fine branching 

 vessels (interlobular branches). These unite in the centre of the 

 lobule to form an intralobular vessel, which joins with others to make 

 a sublobular vein, the fusion of sublobular veins finally forming the 

 hepatic vein. The large branches of this gape open when the liver is 

 cut. The bile canaliculi, the first comemncement of the bile ducts, are 

 channels between the liver cells, and can be demonstrated by giving 

 such a dye as sulph'ndigotate of soda. This is secreted with the 

 bile, and distends and stains the canaliculi. They can also be stained 

 by Golgi's method. 



The liver is an organ of manifold functions, some of which have 

 already been mentioned or Jealt with. We propose in this section 

 to group together the various functions of the organ in order that 

 the scope of its activities may be appreciated. 



1 . The Formation and Excretion of Bile. Within the liver the bile 

 salts are synthesized, and the bile pigments are derived from the 

 haemoglobin of effete blood -corpuscles. These, together with the other 

 constituents of the bile, are secreted into the bile canaliculi, and pass 

 thence into the intestine, there to fulfil the various functions already 

 indicated (see p. 391). 



2. The Glycogenic Function. The liver acts as the storehouse of 

 the colloid glycogen. This it forms from the dextrose brought by 

 the portal vein, and under appropriate circumstances reconverts it 

 into dextrose for use in other parts of the body, particularly in the 



447 



