Kidney

The kidneys are bean shaped organs that serve several essential regulatory roles. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and regulation of blood pressure (via maintaining salt and water balance). Kidneys act to filter the blood, and remove water soluble wastes, which are diverted to the urinary bladder.

In producing urine, the kidneys excrete wastes such as urea and ammonium, and they are also responsible for the reabsorption of water, glucose, and amino acids. The kidneys also produce hormones including calcitriol, erythropoietin, and the enzyme renin.