THE URINARY BLADDER 



195 



tudinal layers, with a circular layer between them. The muscular 

 layers are not well marked. The internal vesical sphincter is 

 formed from an increase in the thickness of the circular layer. 

 Numerous minute ganglia are found along the nerves of the blad- 



FIG. 123. VERTICAL SECTION OP THE LINING PORTION OF THE BLADDER (MALE) 

 BEHIND THE TRIGONE. STAINED WITH ELEMATOXYLIN AND EOSIN (X400). 



A. Connective tissue of sub-epithelial region. 



B. Capillary supply of sub-epithelial region. 



C. Muscular wall of bladder. 



D. Deep cells of the epithelial lining. 



E. Middle region of lining. 



F. Detached surface cells, showing processes beneath. 



G. Thin surface cells in profile. 



H. Squamous surface cells, seen detached, in plan. 

 I. Vacuolated cells. 



der, which contain both medullated and non-medullated fibers. 

 As in the ureter, the blood supply of the mucous and muscular 

 coats is abundant. Small nodules of lymphoid tissue occur in 

 the mucous membrane. The epithelium is transitional ; but the 

 disposition of the cells varies with the extent to which the bladder 

 is expanded. 



Prepare sections of human bladder in the same manner as sections were 

 made of the ureter. 



