The urinary system is responsible for removing the body's extra water and the byproducts of human metabolism.  The kidneys act as blood filters removing water and byproducts that dissolve in water.  Blood flows through the kidneys where most of the water is removed and this fluid travels through the ureters to the bladder. This fluid now called urine is then removed from the body through the urethra. The hero of the urinary system is the kidney.  The kidney has an amazing ability to remove chemicals and electrolytes from the blood actively. This means that they kidney uses energy to actively pull electrolytes out of of the blood.