540 



THE URINARY APPARATUS 



XXXVI. 



at the hilus, and divides into branches that pass towards the cortex,, 

 then turn over and form incomplete arches in the region between 

 cortex and medulla. From these arches vessels pass to the surface 



which are called the interlobular 

 arteries ; they give off vessels 

 at right angles, which are the 

 afferent vessels of the glomeruli' 

 a glomerulus is made up of 

 capillaries as previously stated. 

 From each, a smaller vessel (the 

 efferent vessel of the glomerulus) 

 passes out, and like a portal 

 vessel on a small scale, breaks 

 up once more into capillaries 

 which ramify between the con- 

 voluted tubules. These unite to 

 form veins (interlobular veins) 

 which accompany the inter- 

 lobular arteries; they pass to 

 venous arches, parallel to, but 

 more complete than the corre- 

 sponding arterial arches; they 

 ultimately unite to form the 

 renal vein that leaves the hilus. 

 These veins receive also others 

 which have a stellate arrange- 

 ment near the capsule (vena? 

 stellulce). 



The medulla is supplied by 

 pencils of fine straight arterioles 

 which arise from the arterial 

 arches. They are called arterice 

 rectce. The efferent vessels of 

 the glomeruli nearest the me- 

 dulla may also break up into 

 similar vessels which are called 

 false arteries rectce. The veins 

 (vence rectce) take a similar course 

 and empty themselves into the 

 venous arches. In the boundary 

 zone groups of vasa recta alter- 

 nate with groups of tubules, and give a striated appearance to this 

 portion of the medulla. 



The Ureters The duct of each kidney, or ureter, is a tube 

 about the size of a goose-quill, and from twelve to sixteen inches in 



FIG. 419. Vascular supply of kidney, a, part of 

 arterial arch ; b, iuterlobular artery ; c, glo- 

 merulus ; d, efferent vessel passing to the 

 medulla as false arteria recta ; e, capillaries of 

 cortex ; /, capillaries of medulla ; g, venous 

 arch ; h, straight veins of medulla ; i, inter- 

 lobular vein ; j, vena stellula. (Cadiat.) 



