The Secretion of Urine, 



9*4. STRUCTURE OF THE KIDNEY. -[Capsule. The kidney is a compound tubular 

 island and is invested by a thin, tough, fibrous capsule easily stripped off from the substance 

 Sf the organ to which it is attached by fine processes of connective-tissue and blood-vessels.] 



rNaked Eye Appearances. -On dividing the kidney longitudinally from the lnlum to its 

 outer border; and examining the cut surface with the naked eye, we observe the parenchyma 



Boundary layer j 

 of Medulla. \ 



Papillary por- 

 tion of me- 

 dulla. 



Transverse section } 

 of tubules in - 

 boundary layer. ) 



Fat of renal sinus. 4. 



Labyrinth. 

 / Medullary 



MEDULLA. 



Transversely ) . * - * - 



coursing medul- - *^Lc**=~- fisSSF 



Artery. 5. 



Artery, ft, 



. / Branch of 

 A \ renal artery. 



Fig 240. 

 Longitudinal section through the kidney (Tyson, after Henle). 



of the kidney, consisting of an outer cortical and an inner medullary, or pyramidal portion, 

 the latter composed of about twelve conical papillae, or pyramids of Malpighi, with their apices 

 directed towards and embraced by the calices of the pelvis of the kidney (fig. 240). The 

 medullary portion is further subdivided into the boundary layer of Ludwig and the papillary 



