260 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



sure, the renal sinus. The pelvis is a funnel-shaped 

 expansion of the ureter that occupies a large portion 

 of the sinus. The contents of the sinus may be re- 

 moved, when the exposed wall will be found to be 



kidney substance. 

 Each kidney is 

 enclosed in a 

 smooth fibrous cap- 

 sule of areolar tis- 

 sue, a part of which 

 also lines the sinus. 

 The capsule is 

 finely vascular and 

 can easily be de- 

 tached. If it ad- 

 heres to the kidney 

 substance it is evi- 

 dence of disease. 



It is customary 

 to describe the kid- 

 ney as made up of 

 two layers, an out- 

 er, or the cortex, and 

 an inner, the me- 

 dulla, although 

 there is no sharp 



Fig. 198. Longitudinal section 

 through the kidney: I, Cortex; i', medul- 

 lary rays; i", labyrinth; 2, medulla; 2', 

 papillary portion of medulla; 2", boun- 

 dary layer of medulla; 3, transverse sec- 

 tion of tubules in the boundary layer; 4, 

 fat of renal sinus; 5, artery; *, transverse 



medullary rays; A, branch of renal artery; 

 C, renal calyx; U, ureter (after Tyson 

 andHenle). 



line dividing the 

 two. The medulla 

 consists of ten or 



twelve separate conical masses called Malpighian, or 

 medullary pyramids, so arranged that their bases bor- 

 der on the cortical layer and their apices point toward 



