Urinary system

The urinary system, also known as the urinary tract or renal system, is a part of the excretory system of vertebrates. In humans and placental mammals, it consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. The urinary tract is the body's drainage system for the eventual removal of urine.^[1] The kidneys have an extensive blood supply via the renal arteries which leave the kidneys via the renal vein. Each kidney consists of functional units called nephrons. Following filtration of blood and further processing, the ureters carry urine from the kidneys into the urinary bladder. During urination, the urethra carries urine out of the bladder through the penis or vulva. The female and male urinary system are very similar, differing only in the length of the urethra.^[2]

800–2,000 milliliters (mL) of urine are normally produced every day in a healthy human. This amount varies according to fluid intake and kidney function.