About one-quarter (750-1,000 pints daily) of the blood which is output by the heart is sent to the body's "filter treatment plant", where it is purified by the kidneys and circulated on to the rest of the body. 

One to two thousandths (1/1000-2/1000) of the blood flow becomes fluid waste and is sent into the bladder for storage until it can be conveniently expelled. This toxic waste is called urine. 

The kidneys are located about two inches above the body's midline just below and behind the liver in the upper abdomen and behind the lower ribs. They receive about 120 pints of blood per hour, even if other body systems are shorted. 

They are the balancers of internal fluids, so if we overeat or overdrink one day and diet the next, or if we have an active, "sweaty" day, the kidneys will compensate and see that these fluctuations in fluid, salt and glucose are leveled out. It is important to drink plenty of fluids each day to keep the kidneys in good working order. The "kidney" bean is so named because of its resemblance to the shape and color of the kidneys. Many people believe the kidneys lie down in the flanks and are surprised when pain from kidney disorder comes from the upper middle back area. Well, I have "to go" now.