What is the duct called through which urine passes from the kidney to the bladder?

The duct that carries urine from the kidney to the bladder is known as the ureter. Each kidney is connected to the bladder by one ureter, and these tubes are critical for the urinary system. They transport urine, which is produced in the kidneys, through a peristaltic motion that pushes urine continuously down into the bladder for storage until it is excreted from the body.

In contrast to the ureter, the common duct refers more to duct systems related to bile and pancreatic enzymes rather than the urinary tract. The cystic duct is specifically involved in the bile transport from the gallbladder but does not play a role in urinary transportation. The urethra, while being a significant part of the urinary system, has a different function; it is the duct through which urine is expelled from the bladder to the outside of the body. Thus, the ureter is the correct answer because it precisely describes the structure responsible for transporting urine from the kidneys to the bladder.