STRUCTURE OF THE KIDNEY 



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into an outer layer, known as the cortical substance, and an inner, 

 or pyramidal, portion. Internally the incision reveals a cavity 

 into which the ureter opens. This is the pelvis. 



2" 



FIG. 54. Longitudinal section through the kidney, the pelvis of the kidney, 

 and a number of renal calyces. (From Brubaker, after Tyson.) 



A, branch of the renal artery; U, ureter; C, renal calyx; i, cortex; i', medullary 

 rays; i", labyrinth, or cortex proper; 2, medulla; 2', papillary portion of medulla, 

 or medulla proper;" 2, border layer of the medulla; 3,3, transverse section through 

 the axes of the tubules of the border layer; 4, fat of the renal sinus; 5, 5, arterial 

 branches; * transversely coursing medulla rays in column of Bertin. 



Tracing the divisions of the pelvis toward the kidney substance, 

 it is found to be continued by three short canals, one toward 



