The kidneys The body’s total blood supply circulates through the kidneys about 12 times per hour. In 24 hours, your kidneys filter around 150 liters of blood and produce roughly 1.5 litres of urine. Kidneys will continue performing until they have lost 75-to-80 percent of their function. The kidneys of a newborn baby are about three times larger, in relation to its body weight, than an adult’s. The kidneys vitamin D. they convert it to an active form that stimulates bone development. You can live a normal life with only 1 kidney- it will perform all the functions of 2 kidneys. About one-third of transplanted kidneys come from living relatives. We hardly give them a thought, but our kidneys work hard for us, Manufacturing essentials chemicals, breaking down dangerous substances and eliminating toxic waste. They also provide the nutrients to care for our bones and joints; control the PH and regulate blood pressure.