RENAL PELVIS AND URETERS 445 



tributing their fibers to the walls of the arteries and veins and to the 

 uriniferous tubules of both cortex and medulla. 



The parenchymal branches form an 'epilemmal plexus' in the in- 

 terstitial connective tissue about all portions of the uriniferous tubule. 

 From this plexus fibrils pierce the membrana propria and anastomose to 

 form a 'hypolemmal plexus' about the base of the epithelial cells. Ter- 

 minal fibrils penetrate between the epithelial cells where they form 

 minute end knobs. 



RENAL PELVIS AND URETERS 



The excretory passages of the kidney include the renal -pelvis, the 

 ureters, the urinary bladder and the urethra. All of these portions 

 possess certain common characteristics. They have three coats, mucous, 

 muscular, and fibrous, and are lined by a common type of epithelium, 





FIG. 410. CAST OP THE PELVIS, INFUNDIBULA AND CALICES OF THE KIDNEYS 



OF A MAN. 



Showing the expansion of the ureter, the subdivision of the pelvis, and the con- 

 cave facets by which the calices fit over the apices of the renal pyramids. (After 

 Hauch.) 



transitional, which extends from the renal pelvis to the prostatic por- 

 tion of the urethra. 



The mucosa of the renal pelvis and ureter is lined by transitional 

 epithelium which rests upon a fibrous tunica propria. Tin- epithelium 

 consists of several cell layers, of which the superficial is formed by broad 



