468 A MANUAL OF PHYSIOLOGY 



the kidney, with diminution or cessation of the secretion of urine. 

 But slow rhythmical stimulation of the roots causes increase of 

 volume, the scanty dilators being by this method excited in prefer- 

 ence to the constrictors. 



The renal nerves, entering at the hilum, branch repeatedly, so as 

 to form a wide-meshed plexus around the arteries, and accompany 

 them even to their finest ramifications in the cortex. Coming off 

 from the nerves surrounding the arteries are fine fibres which are 

 distributed to the convoluted tubules. Some of them terminate in 

 globular ends, others in fine threads that pass through the mem- 

 brana propria (Berkely). 



FIG. 176. NERVES OF KIDNEY (BERKELV). 



(i 6) medium - sized artery with its nerve - plexus ; A, terminal knobs ; 

 B, aberrant branch ending in terminal knob E ; the dotted lines outline the 

 artery; (17) nerve-fibres surrounding a Bowman's capsule, which is indicated 

 by a dotted line ; some of the endings are close to the membrane ; (18) convoluted 

 tubule shown in outline with fine nerve-fibres on it, which seem to enter the 

 basement membrane. 



Section of the renal nerves is followed by relaxation of the 

 small arteries in the kidney, and consequent swelling of the 

 organ. 1 The flow of urine is greatly increased, and sometimes 

 albumin appears in it, the excessive pressure in the capillaries 

 (particularly in those of the glomeruli) being supposed to favour 

 the escape of substances to which a passage is refused under 

 normal conditions. 



An experiment which' is sometimes quoted as a decisive test 

 of the relative importance of changes in the rate of flow, and 

 in the pressure of the blood within the glomeruli, is that of 

 tying the renal vein. This undoubtedly does not lower the 



