The ureters are two thin tubes that connect the kidneys to the bladder. Their primary function is to transport urine, which is produced in the kidneys, down to the bladder for storage. Each ureter is about 10 to 12 inches long and has muscular walls that help push urine through a series of contractions. Ureters are lined with a special type of tissue that helps protect them from the urine's acidity. They enter the bladder at an angle, which helps prevent urine from flowing back into the ureters. This one-way flow is essential for maintaining proper kidney and bladder function.