Functions:
The main function of the ureter is to carry urine from kidney to the urinary bladder. Urine flows down partly by gravity but mainly by wave of contractions, called peristalsis, which pass several times per minute by through the muscle layers of the urethral walls. Each ureter enters the bladder through a tunnel in the bladder wall, which is angled to prevent the urine from running back into the ureter known as reflux, when the bladder contracts.
Diseases:
A kidney stone can move from kidney and become lodged inside the ureter, which can block the flow of urine, which causes sharp cramps in the back and side and lower side of the abdomen. This is very common disorder of ureter. Others are hydronephrosis, hydroureter, obstructive uropathy refers to the functional and anatomical obstruction of urinary flow.
Interesting Facts:
The unidirectional valves are present in ureters which does not make the urine to flow in opposite direction so it flows only towards urinary bladder.
