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 urine from the body, regulate blood volume and blood pressure, control levels of electrolytes and metabolites, and regulate blood pH. 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 transport urine from the kidneys into the urinary bladder. The female and male urinary system are very similar, differing only in the length of the urethra, which transports urine from the bladder through the penis or vulva during urination. Healthy humans normally produce 800–2,000 milliliters (mL) of urine every day. This amount varies according to fluid intake and kidney function.