CHAPTER XXVII. 



URINARY EXCRETORY PASSAGES ; SUPRARENAL CAPSULES. 



BY EDMUND C. WBNDT, M.D., NEW YORK CITY, 

 Curator of the St. Francis Hospital, etc. 



THE renal pelvis, the calices, ureters, and bladder, all consist 

 essentially of three layers, which are an inner mucous mem- 

 brane, a middle muscular coat, and an external fibrous layer. 



In the 



RENAL PELVIS 



we find the mucous membrane lined with stratified epithelium, 

 the cells of which are large and variously shaped. Three dif- 

 ferent forms are readily distinguished. The most superficial 

 layer consists of flat or polyhedral cells of various sizes, each 

 one containing a round or oval nucleus, or, as frequently hap- 

 pens, two nuclei. Peculiar dark granules, often of large size, 

 surround the nucleus, and are quite distinct from the finely 

 granular protoplasm of these cells. Then comes a layer of 

 conical or club-shaped bodies, each one again furnished with 

 a round or oval nucleus. Every cell also possesses a long 

 basal process, which appears to attach it to the subjacent 

 tissue. The bulbous portion of these corpuscles is turned 

 outward in the direction of the surface. Wedged in between 

 the processes just mentioned we find the third variety of 

 cellular elements. These are oval or rounded bodies contain- 

 ing ellipsoid nuclei. At the renal calices we find a sharp line 

 of demarcation between the cylindrical columnar epithelium 

 of the papillary ducts and the stratified pavement epithelium 

 of the pelvis. The epithelial layer has a thickness here of 

 0.045-0.09 mm. 



The connective-tissue portion of the mucous membrane is 

 devoid of papillse, contains sparse elastic fibres, and is rich in 



