Which structure transports urine from the kidney to the urinary bladder?

Which structure transports urine from the kidney to the urinary bladder?

• A. Ureter.
• B. Urethra.
• C. Umbilical artery.
• D. Renal papilla.

Answer: (A)

Urine moves from the kidney to the bladder through a muscular tube called the ureter. The ureter collects urine from the renal pelvis and uses rhythmic smooth-muscle contractions, or peristalsis, to push it downward toward the urinary bladder. Its lining is transitional epithelium, and its muscular layers help coordinate unidirectional flow so urine doesn’t back up. At the point where it enters the bladder, the ureter forms a protective angle that helps prevent reflux. The other structures don’t transport urine from kidney to bladder: the urethra carries urine out of the body, the umbilical artery is a fetal blood vessel, and the renal papilla is the tip of a renal pyramid where urine enters the calyx.

Urine moves from the kidney to the bladder through a muscular tube called the ureter. The ureter collects urine from the renal pelvis and uses rhythmic smooth-muscle contractions, or peristalsis, to push it downward toward the urinary bladder. Its lining is transitional epithelium, and its muscular layers help coordinate unidirectional flow so urine doesn’t back up. At the point where it enters the bladder, the ureter forms a protective angle that helps prevent reflux. The other structures don’t transport urine from kidney to bladder: the urethra carries urine out of the body, the umbilical artery is a fetal blood vessel, and the renal papilla is the tip of a renal pyramid where urine enters the calyx.