07.02 Kidneys

The kidneys have two major functions. They remove wastes such as urea from the breakdown of proteins and potentially harmful substances such as drugs and toxins from the blood and excrete them in the urine.Additionally they are involved in maintaining homeostasis of body fluids. They achieve this by regulation of water volume and sodium content to maintain blood pressure; regulation of potassium ions for neuron, muscle and heart functioning and regulation of the concentration of H+ ions to maintain acid base balance.

Blood enters the kidneys via renal arteries and the blood that has been filtered at the nephrons leaves the kidneys via renal veins. The nephrons produce the urine which is transported to the bladder via the ureters(Figure 7.2).

Figure 7.2 A kidney showing its blood supply (Copyright, QUT)