Doctors can often see a large hiatus hernia on a chest x-ray. Otherwise, people are given barium in a liquid before x-rays are taken (barium swallow). The barium outlines the esophagus, making abnormalities easier to see. Hernias can also be seen during an upper endoscopy.
The kidneys filter the blood to remove wastes and produce urine. The ureters, urinary bladder, and urethra together form the urinary tract, which acts as a plumbing system to drain urine from the kidneys, store it, and then release it during urination.
Most of this nitrogenous waste is converted by the kidneys into a chemical called urea which is removed during urination. Other substances are also excreted, but urea makes up the bulk of the dissolved substances in urine.   Sweating, however, serves a different function.