our kidney extract about 180 fluid call fitrate consisting of water urea and number of valuable solutes including glucose aminoacid ion and vitamin if we excreted all the the filtrate as urine we would lost vital nutrient and dehydrate rapidly. instead our kidney refine the filatrateconnecting the urea and recuycling most of the water anduseful solute to the blood in atypical day we excrete only about105l of urine