THE KIDNEY 



439 



divisions of the kidney and that, therefore, each of the subdivisions 

 contains only certain characteristic portions of the renal tubule. Thus 



are found in the 

 CORTICAL LABYRINTH. 

 (1'ars Convolute) 



CORTICAL KAYS 



(Pars radial a) 



BOUNDARY ZONE OF THE 

 MEDULLA. . 



1 1 enal corpuscle. 

 Neck of the tubule. 

 Proximal convoluted portion. 

 Distal convoluted portion. 

 Arched collecting portion. 



f Spiral portion of the convoluted tubule. 

 J Ascending limb of Henle's tubule. 

 [Straight collecting portion. 



Descending limb of Henle's tubule. 

 Ascending limb of Henle's tubule. 

 '[Straight collecting portion. 



f Descending limb of Henle's tubule. 

 PAPILLARY ZONE OF THE Loop of Henle's tubule. 



MEDULLA 1 Straight collecting portion. 



[ Papillary duct. 



The following outline, based upon the investigations of Peter, gives a 

 more detailed classification of the different portions of the renal tubule 

 in the medulla : 



1. Outer stripe 



(a) straight collecting tubules. 



(b) proximal convoluted tubules. 



A. Outer Zone (c) thick ascending limbs of Henle's loops, 



including both 



(x) thick cloudy portions, and 

 (y) thick clear portions. 



2. Inner stripe 



(a) 



MEDULLA- 



thin clear descending limbs of Henle's 



loops. 

 , (b) thick cloudy portion of ascending 



limbs of Henle's loops. 

 (c) short loops of Henle, of thick cloudy 



type of epithelium. 

 B. Inner Zone 



(a) straight collecting tubules. 



(b) long- loops of Henle, entirely of thin clear type of 



epithelium. 



