222 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



pathetic nerves associated with the intestine. If 

 there is an obstruction to the free passage of bile, as 

 in the passage of a calculus, the musculature of the 

 ducts contracts violently and spasmodically, giving 

 rise to the characteristic pain of plain muscle con- 

 traction described on page 94. If the obstruction 

 occurs in the hepatic or the common duct, the liver 

 becomes saturated with bile which is absorbed by the 

 blood, and jaundice follows. If the obstruction is 

 in the cystic duct the liver does not suffer and there is 

 no jaundice. 



Smaller Excretory Bile Ducts and Gall Bladder. 

 Small bile ducts of the liver begin within the liver 

 lobules, , where they form a complex system of anas- 

 tomosing channels or tubes called bile canaliculi. 



Interlobular Ducts. The bile canaliculi unite to 

 form interlobular ducts that lie between the liver lob- 

 ules. These unite into larger and larger ducts and 

 converge to>pass out through the transverse fissure, 

 where five or six ducts are found. The latter unite 

 into two short main ducts that drain respectively 

 from the right and left lobes of the liver. 



The hepatic duct is formed by the union of the two 

 main ducts at the bottom- of the transverse fissure 

 and thus receives the bile from the whole liver. It is 

 from one to one and one-quarter inches in length and 

 one-quarter inch in breadth, and extends downward 

 from its origin, taking an irregular course, to its 

 junction with the cystic duct, which unites with it to 

 form the common bile duct. $ 



The gall bladder, with its cystic duct, is an evagina- 

 tion of the bile duct.- The gall bladder is a pear- 



