LIVER. 203 



sphincter (8). From this, certain fibres (X) run down along 

 the sides of the intestine. Others (K) run from one side of 

 the common bile duct to the other surrounding the duct of 

 Wirsung. 



Gall Bladder. 



The gall bladder has been studied recently by M. T. Sudler, 

 and the following account is based largely on the description 

 given by him. The wall consists of the following coats : 

 mucous, fibro-muscular, subserous, and serous. 



The mucous coat is somewhat corrugated on its surface, the 

 folds corresponding with ridges in the underlying fibro-muscu- 

 lar coat. They are covered by a single layer of columnar epi- 

 thelial cells. No goblet cells are present. Fat droplets have 

 been observed in these cells after chyle absorption. A few 

 mucous glands are found in the tunica propria of the mucosa, 



The fibro-muscular coat is composed of a framework of con- 

 nective tissue in which bands of smooth muscle are laid down. 

 According to Hendrickson, there are no definite layers of 

 muscle in the gall bladder. Others have described three 

 indefinite layers, of which the thickest runs transversely. The 

 portion of the fibro-muscular coat just beneath the mucosa is 

 made up almost entirely of connective tissue. It corresponds 

 with the submucosa of many organs. In it there are solitary 

 lymph follicles and many blood- and lymph- vessels. 



The subserous coat is made up of interlacing bands of elas- 

 tic tissue fibrils. The serous coat is the reflection of the perito- 

 neum on the surface of the gall bladder. 



The blood-vessels penetrate the bladder wall and divide in 

 the fibro-muscular coat near the subserous layer. Arterial 

 branches are given off to the mucosa, in which there is formed 

 a fine network. Fine branches run also to the subserous and 

 serous coats. The veins collect in the fibro-muscular coat. 



Over the surface of the gall bladder run large lymphatics, 

 which are derived from the liver and from the coats of the gall 

 bladder. In the subserous layer there is a network of irregu- 

 lar lymph channels which receive the lymph from a plexus of 



