168 



THE ESSENTIALS OF HISTOLOGY 



convoluted tubules, into which these pass. On the other hand, the 

 junctional tubule has a large lumen and is lined by clear flattened 

 cells, and the collecting tubes have also a very distinct lumen and are 

 lined by a clear cubical or columnar epithelium (figs. 201, d ; 204, a). 



"a^^m^M 





FIG. 205. SECTION ACROSS A PAPILLA OF THE KIDNEY. (Cadiat.) 



a, large collecting tubes (ducts of Bellini ) ; 6, c, d, tubules of Heiile ; e,f, blood-capillaries. 



The following gives a tabular view of the parts which compose a 

 uriniferous tubule, and the nature of the epithelium in each part : 



Portion of tubule 



Nature of epithelium 



Position of tubule 



Capsule 



First convoluted 



tube 

 Spiral tube 



Small or descend- 

 ing tube of 

 Henle 



Loop of Henle . 



Larger or ascend- 

 ing tube of 

 Henle 



Zigzag tube 



Second convo- 

 luted tube 



Junctional tube . 



Straight or col- 

 lecting tube 

 Duct of Bellini . 



Flattened, reflected over glomerulus . 

 Cubical, nbrillated, ciliated, the cells 



interlocking 

 Cubical, hbrillated (like the last) 



Clear, flattened cells . 



Like the last 



Cubical, nbrillated, sometimes imbri- 

 cated 



Cells strongly nbrillated ; varying in 



height ; lumen small 

 Similar to first convoluted tube, but 



cells are longer, with larger nuclei, 



and they have a more refractive 



aspect 

 Clear flattened and cubical cells 



Clear, cubical and columnar cells 

 Clear, columnar cells .... 



Labyrinth of cortex 

 Labyrinth of cortex 



Medullary ray of cor- 

 tex 



Boundary zone and 

 partly papillary zone 

 of medulla 



Papillary zone of 

 medulla 



Medulla, and medul- 

 lary ray of cortex 



Labyrinth of cortex 

 Labyrinth of cortex 



Labyrinth passing to 



medullary ray 

 Medullary ray and 



medulla 

 Opens at apex of 



papilla 



