Last reviewed 01/2018

The normal kidney has three functions:

  • the excretion of waste products
  • the homeostatic control of extracellular fluid volume and composition
  • hormone production i.e. renin, erythropoietin & calcitriol

There are 1 million basic functional units, called nephrons, in each kidney.

Nephrons are composed of:

  • glomeruli - where a selective ultrafiltrate of the blood is formed
  • tubules - where selective reabsorption of filtered water and solutes occurs

Also vital to the function of the kidney are:

  • the blood vessels
  • the interstitium