Which organ is NOT part of the urinary system?

The lungs are not part of the urinary system. The primary function of the urinary system is to filter blood, remove waste products, and regulate fluid and electrolyte balance in the body. This system includes the kidneys, ureters, bladder, and urethra.

The kidneys are responsible for filtering blood to produce urine, while the ureters transport urine from the kidneys to the bladder, where it is stored until elimination. The urethra then carries urine out of the body. In contrast, the lungs are part of the respiratory system, which is involved in gas exchange—taking in oxygen and expelling carbon dioxide. Their function is unrelated to the filtration of waste or the management of bodily fluids, which clearly delineates them from the components of the urinary system.