Caption

Kidneys. Coloured computed tomography (CT) scan of an axial section through the abdomen showing the kidneys (lower left/right, in white rectangles). The kidneys filter the blood, removing waste products and passing them to the bladder to be excreted in urine. Also seen on this scan is part of a vertebra (black, between kidneys) and the aorta (black circle, above vertebra). CT scans use many beams of X-rays to build up slice images through the body.