Kidneys are a filter system. The main job of the kidneys is to remove waste from the blood and return the cleaned blood back to the body. Each minute about one litre of blood ï­ one-fifth of all the blood pumped by the heart - enters the kidneys through the renal arteries.
The volume of helium in the balloon has been estimated as being able to lift a total load, including the balloon material and the structure beneath it, of 65 pounds (29 kg) at sea level and 48 pounds (22 kg) at 8,000 feet (2,400 m).
The pill, called the Obalon balloon, is a capsule containing an a balloon. As CBS Newsâ Alphonso Van Marsh reports, after a patient swallows the pill, surgeons inflate the balloon inside to make them feel full and eat less. The device is not permanent though, and needs to be removed after about three months.