High Quality Content by WIKIPEDIA articles! Urine is a liquid product of the body that is secreted by the kidneys by a process called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream. This waste is eventually expelled from the body in a process known as micturition, the primary method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis. Amniotic fluid is closely related to urine, and can be analyzed by amniocentesis.