# Urine --- **Urine** is a waste product excreted by the [[urinary system]]. After the filtrate exits the [[kidneys]] via the ureters the substances is officially considered urine. It travels to the [[bladder]] where it is stored until [[urination]] occurs, where it empties out of the body. Healthy urine is straw yellow, clear, with a distinct odor. It is composed of: - 95% water, 5% solutes - nitrogenous wastes: [[urea]], uric acid, [[creatinine]] - solutes also include - sodium, potassium, phosphate, sulfate, calcium, magnesium, bicarbonate - occasionally it may include some hormones, drugs, and small amounts of ketone bodies. >[!biology] Smelly! >The smell of urine when it is fresh is called **urinoid**, and it takes on an ammonia smell after a while because bacteria break down [[urea]] into [[ammonia]]. A [[urinalysis]] is a test that can be run on the urine to get a lot of useful information on one's overall health, including kidney and even liver function. ___