The |bladder| is a sac-like organ composed of musculomembranous |fiber|. Located in the |pelvis|, the |bladder| stores ~urine~ until it is excreted. The ~urine~ is passed to the |bladder| through |ureters| from each |kidney| in peristalytic (contractile) waves. During excretion, the urethral orifice below the |bladder| is opened and the ~urine~ passes through the |urethra|. Though the urge to void the |bladder| of ~urine~ generally occurs when it has about 250 - 300 milliliters (8 - 10 ounces) in it, the average human |bladder| can hold almost twice this amount. An average human excretes one to two quarts (or one to two liters) of ~urine~ per day, though this is greatly dependent upon the health, diet, and level of activity of the adult. Ingested water usually is excreted within four hours of ingestion.
Urine is usually clear or yellow, though this depends upon the diet and health of the individual. ~Urine~ has a distinct, ammonia-like smell which is primarily due to the nitrogenous wastes which make up 5 % of the ~urine~. The chief constituent of these wastes is ~urea~, though ammonia, uric acid, creatinine, and a host of other waste products also are present.
