258 



HUMAN ANATOMY. 



into the calices of the pelvis within the sinus of the kidney. 

 The renal pyramids of Malpiglii, about ten to fifteen in number, 

 corresponding to the foetal lobules, are arranged into three irregu- 

 lar rows. The substance, or parenchyma of the kidney, is com- 

 posed of uriniferous tubules, held together by comparatively little 



PIG. 123. 



Longitudinal section of kidney: 1, cortex; 2, medulla; 3, section 

 of tubules in boundary layer; 4, fat of renal sinus; 5, renal ar- 

 teriole; A, branch of renal artery; C, renal calyx; U, ureter. 



connective tissue. The terminal orifices of these, several hundred 

 to each papilla, open on its summit. 



Course of the Tubuli Uriniferi. Beginning at the Mal- 

 pighian capsule within the cortex, each tubule pursues a very 

 tortuous and complicated course before it terminates in the renal 

 papilla?, the outline of which is as follows (after Gray) : 



