TUBULI URINIFERI 



423 



next passes almost vertically downward toward the medulla, forming the 

 spiral tubule, still within the cortex of the kidney, which is of much the same 

 diameter. The loop of Henle, L, in the medulla, is a very narrow tube lined 

 with flattened nucleated cells. Passing vertically upward from the loop of 



LABYRINTH \MF.IXRAY\LABYR. 



PC I v it 



FIG. 287. Scheme of Uriniferous Tubule and of the Blood Vessels of the Kidney, 

 Showing Their Relation to Each Other and to the Different Parts of the Kidney. G, 

 Glomerulus; BC, Bowman's capsule; N, neck, PC, proximal convoluted tubule; 5, spiral 

 tubule; D, descending arm of Henle's loop;L, Henle's loop; A, ascending arm of Henle's 

 loop; IDC, distal convoluted tubule; AC, arched tubule; SC, straight collecting tubule; 

 ED, duct of Bellini; A, arcuate artery, and V, arcuate vein, giving off interlobular vessels 

 to cortex and vasa recta to medulla; a, afferent vessel of glomerulus; e, efferent vessel of 

 glomerulus; c, capillary network in cortical labyrinth; s, stellate veins; vr, vasa recta and 

 capillary network of medulla. (Pearsol.) 



Henle, the tubule varies somewhat in histological character, but the irregular 

 tubule and the distal convoluted tube, identical in all respects with the proxi- 

 mal convoluted tube, are to be noted. The proximal convoluted tubes 

 pass into the curved and straight collecting tubes, the latter running 

 vertically downward to the papillary layer, and, joining with other collecting 



