Caption

Healthy urinary tract. Coloured urogram (X-ray) of healthy human calyces, ureters and bladder (all yellow). The calyces are the two branching structures in the upper frame on either side of the spine. They are the collecting ducts for urine within the kidneys. Descending from these are the ureters, the tubes that carry urine to the bladder. The bladder, between the hip joints at bottom, temporarily stores the urine. Urograms are made by injecting an X-ray opaque substance into the blood and then taking an X-ray when it has been filtered out of the blood by the kidneys. This technique is used to look for disorders of the urinary system, such as kidney stones.