Final answer:
The ureter is a muscular tube about 10 inches long that carries urine from each kidney to the bladder, using peristalsis to move urine efficiently. This structure is not to be confused with the urethra, which is the tube leading from the bladder out of the body.
Step-by-step explanation:
The muscular tube about 10 inches long that carries urine to the bladder is known as the ureter. Each kidney has a ureter that connects to the bladder. The walls of the ureter consist of smooth muscle that contracts in a wave-like motion, a process called peristalsis, efficiently moving urine toward the bladder. This muscular layer contains both longitudinal and circular muscles which engage to propel the urine without reliance on gravity.
The urethra is another critical part of the urinary system but is different from the ureters. While both structures are involved in urine transport, the urethra is specifically the tube that carries urine out of the body from the bladder. The urethra varies in length between individuals with XY chromosomes (anatomically male) and those with XX chromosomes (anatomically female), also serving a dual function in males by transporting semen as well as urine.