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.
Uric acid waste. Uric acid is less toxic than urea and is also excreted by the kidneys, and while it is a bigger molecule than urea and less soluble, the uric acid that appears in urine is mostly secreted by the tubule cells in the kidneys. Uric acid is formed from the metabolism of nucleic acids.