Urogram (X-ray) of the healthy kidneys of a 38 year old male patient. On either side of the spine (running down centre) are the branching structures of the calyces (white), which collect urine from the kidneys. Descending from the calyces are the ureters (tubes) which carry urine from the kidneys to the bladder. Urine is a waste product produced in the kidneys by filtering blood. A urogram is taken by injecting a radiopaque liquid into the blood and taking an X-ray of the urinary system once the blood has been filtered.