Urine (from Latin Urina, ae, f. ) is a typically sterile liquid by-product of the body secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream. These by-products are eventually expelled from the body during urination, the primary method for excreting water-soluble chemicals from the body.