Urine (from LatinUrina,ae,f.) is a liquidby-product of the body secreted by the kidneysthrough a process called urination(or micturition) and excretedthrough the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require clearancefrom the bloodstream. These by-products are eventually expelled from the body during urination, the primary method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis. Human urine together with human fecesare collectively referred to as human wasteor human excreta .Urinationis the release of urinefrom the urinary bladderthrough the urethrato the urinary meatusoutside of the body. It is also known medically asmicturition,voiding,uresis, or, rarely,emiction, and known colloquially by various names includingtinkling,peeing,weeing, andpissing. In healthy humans (and many other animals) the process of urination is under voluntary control.