432 



THE URINAKY SYSTEM 



which region only they occur. This portion of the tubule is remarkable 

 for the irregularity of its course, it being twistedand bent upon itself in 

 a most tortuous manner. Arising at the renal corpuscle, it at first passes 

 toward the surface of the organ, but soon turns about and runs toward 



w/ 



FIG. 403. FROM THE CORTEX OF THE HUMAN KIDNEY, SHOWING A TRANSECTION 

 OF A CORTICAL RAY IN THE LOWER LEFT-HAND CORNER. 



a, glomerulus; 6, glomerular capsule; c, proximal convoluted tubule; d, collecting 

 tubule; e, ascending limb of Henle's tubule;/, spiral tubule; g, blood-vessel; h, distal 

 convoluted tubule. Hematoxylin. X 200. (After Schaper, from Stohr.) 



the medulla, at first with extreme convolutions, but later pursuing a 

 rather spiral course (spiral tubule). On reaching the border of the 

 medulla the tubule becomes sharply constricted and entejrejthje_medullary 

 boundary zone at the thin descending limb of Henle's loop. 



