LIVER 



287 



and to some extent leucocytes are formed, but in the adult the recticulum 

 is free from cells. The endothelial cells, moreover, do not fit closely 

 together, and are known as the stellate cells of Kupffer. It is probable 

 that, whereas the blood flows through the capilliform sinusoids toward the 

 central vein, there is a current of tissue fluid in the reticulum taking the 

 reverse direction and passing toward the portal canal. This fluid is the 

 source of the great quantity of lymph which flows from the liver. 



According to S chafer (Quain's Anatomy, 1912, vol. 2) the blood flowing 

 through the sinusoids comes into direct contact with the liver cells. He 



States that blood COrpUSCleS Hepatic trabeculse . Blood corpuscles. Reticulum. 



may occasionally be found ^ \ 



normally within the hepatic \" 



cells, into which they are 

 readily forced by injections 

 at low pressure; and he de- 

 scribes canaliculi within "the 

 protoplasm of the hepatic 

 cells, which communicate 

 with the sinusoidal blood 

 vessels. These canaliculi 

 are presumably secretory 

 channels or canals of the 

 trophospongium, which have 

 been artificially invaded by 

 the injection. At the same time, the reticulum has been compressed and 

 its significance obscured. 



Portal canals. The portal canals are strands of connective tissue 

 extending into the liver from the transverse fissure or porta (which is 

 essentially a hilus). They constitute the interlobular tissue of the liver, 

 and the ducts, arteries, and veins which they contain are often called inter- 

 lobular. In addition to the structures already considered, the portal 

 canals contain lymphatics and nerves; these and certain features of the 

 ducts require further consideration. 



The lymphatic vessels are abundant, forming plexuses around the ducts 

 and blood vessels, and receiving fluid from the perivascular reticulum 

 within the lobules; but no lymphatic vessels enter the lobules. They 

 pass out of the liver at the porta, where lymph glands are found. Certain 

 of the lymphatics in the capsule of the liver drain toward the porta; 

 others enter the diaphragm. 



The nerves are chiefly non-medullated fibers from the sympathetic 

 system, but the liver also receives branches from the vagus. These 

 nerves are principally distributed to the blood vessels, but some are said 

 to penetrate the lobules and end in contact with the hepatic cells. 



FIG. 282. SECTION OF THE LIVER PREPARED BY THE BIEL 

 SCHOWSKY METHOD. X 300. 



