164 



NORMA L HISTOL 00 Y. 



Fig. 139. 



Diagram showing the course of the renal tubules within the kidney. (Klein.) A, cortex : a, 

 subcapsular portion destitute of Malpighian bodies ; a', inner portion, also devoid of Mal- 

 pighian bodies. B, boundary. C, portion of the medulla at the base of the pyramid. 

 1, Bowman's capsule surrounding the glomerulus ; 2, neck of the capsule and beginning 

 of the uriniferous tubule: 3, first convoluted tubule; 4, spiral portion of the first con- 

 voluted tubule in the medullary ray; 5, descending limb of Henle's tube; 6, Henle's 

 loop ; 7, 8, 9, ascending limb of Henle's tube ; 10, irregular transition to the second con- 

 voluted tubule; 11, second convoluted tubule; 12, transition from second convoluted 

 tubule to the collecting tubule ; 13, 14, collecting tubule, joined below by others to form 

 the excretory duct, which opens at the apex of the pyramid. 



tubule, it will be best to complete this general sketch by considering 

 the course of the bloodvessels. 



As has already been said, the vessels enter the kidney between 

 the calices and pyramids and are distributed in branches that lie 





