THE KIDNEY 



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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. 

 (Pars Convoluta) 



CORTICAL RAYS . . 

 (Pars radiata) 



BOUNDARY ZONE OF THE 

 MEDULLA . . 



PAPILLARY ZONE OF THE 

 MEDULLA. , 



Renal 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. 



Descending limb of Henle's tubule. 

 Loop of Henle's tubule. 

 Straight collecting portion. 

 Papillary duct. 



MEDULLA^ 



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. 

 Inner stripe 



(a) 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. 

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