The urinary system, also known as the renal system consists of the kidneys, bladder, ureters and the urethra. The purpose of the urinary system is to eliminate waste from the body to maintain blood pressure and blood volume. It regulates blood pH and control levels of electrolytes and metabolites.

Through filtration of blood, urine is formed in the kidneys. Then urine passed through the ureters to the bladder, where it is stored. And then passed from the bladder to the outside of the body through the urethra.

2 litres of urine is normally produced every day in a healthy human. This amount varies according to fluid intake and kidney function.

The functional unit of the kidney is the nephron. Its chief function is to regulate the concentration of water and soluble substance, filtering the blood and reabsorbing.

The nephron in which Bowman's capsule filters the blood from the circulatory system into the tubules. The filtrate includes water, small ions, and molecules that easily pass through the filtration membrane because of small in size, larger molecules such as proteins and blood cells are prevented from passing.