Urine concentration is established by bringing tubular fluid down though the increasing osmotic gradient established by the Loop of Henle. ADH controls water permeability of the tubule. The blood supply to the nephron. Blood flow through the kidney is not homogeneously distributed. The composition of the glomerular fluid vs. plasma.
Tubular fluid is an ultrafiltrate, meaning that it is relatively free of plasma proteins.
The ionic concentration of diffusible ions in tubular fluid differs slightly from plasma because of the Donnan effect. Topic 5 . There are 500,000 nephrons in the canine kidney and 175,000 nephrons in the feline kidney. The sympathetic nervous system and vasoactive agents can affect the total GFR of the kidney. Describe the consequence of changing afferent and efferent arteriole tone, then describe how GFR changes with as a result of sympathetic nervous system activity and vasoactive agents.