For 10 points, name this liquid waste product that is excreted by the kidneys, stored in the bladder, and discharged through the urethra.
The kinin system was discovered upon realization that injection of it leads to low blood pressure, and the surface tension of it is measured in the Hay test. One disease affecting it in infants is a result of a mutation in the BCKDHA gene, prevents the breakdown of leucine, isoleucine, and valine, and results in it smelling like maple syrup. Albumen is found in it in sufferers of Bright's disease, and it normally contains hippuric acid, creatinine, urea, and other nitrogenous compounds. For 10 points, name this liquid waste product that is excreted by the kidneys, stored in the bladder, and discharged through the urethra.
The kinin system was discovered upon realization that injection of it leads to low blood pressure, and the surface tension of it is measured in the Hay test.
{urine} [or {pee}; or other synonyms]