Ureters are a pair of muscular tubes that run from the kidneys to the urinary bladder where the urine is stored before excreting it. In humans, there are two kidneys, one for each kidney. The upper half of the Ureter is located in the abdomen whereas the lower half is in the pelvic area. Urine flows down partly due to gravity, but it is mostly due to the waves of contractions, which pass frequently every minute through the muscle layers of the walls of urethra. It is through a tunnel in the bladder wall through which each Ureter enters the bladder. The tunnel is angled in a way that when the bladder contracts it prevents the urine from running back into the Ureter.
A Ureter has an average length of 25 to 30 cms with a diameter of nearly 5 mms. A Ureter is made up of three layers of tissues which are the innermost mucous coat, the outermost fibrous and the muscular coat between the both. These layers give a shape of the star to the space inside the Ureter. Similar to renal pelvis, bladder, and proximal urethra, the Ureter is lined with transitional cell epithelium, which comprises short basal layer, one or more layers of columnar cells and most acutely, umbrella cells. The umbrella cells specialise in surviving bathing in hypertonic urine and stretching with distention of the lumen.
The lamina propria, an elastic connective tissue matrix lies deep to the epithelial layer. Muscularis is the thickest layer of the Ureter. It is composed of smooth muscles oriented in an inner longitudinal and outer circular arrangement. Finally, adventitia, a fibrous layer that harbors the vascular supply is the outer portion of the Ureter.
The function of the Ureter is to carry the urine from the kidney and transport it to the bladder. The flow of the urine is partly because of the gravity but mainly due to the contraction of the muscular walls.
The major Ureter disorders include the following:
Duplication of Ureter: This is a congenital condition wherein two Ureters form on the same kidney.
Ureteric calculus: Here, the Ureters have the stones, which are produced in the kidneys.
Ureteropelvic Junction Obstruction: When the connection between the Ureter and the kidney is blocked, ureteropelvic junction obstruction occurs. Due to this urine is not able to exit from the kidney.
Ureterovesical Junction Obstruction: In case of this, the connection between the bladder and the Ureter is blocked.
Ureterocele: It is the swelling of the ends of the Ureters, which might also result in blocking the urine.
If any of the above disorders occur, the passage of urine is blocked which can result in pyelonephritis, loss of renal function or renal calculi. Treatment in case of most of the Ureter disorders is possible through insertion of a stent, insertion of a catheter or a surgery. Antibiotics are often prescribed in case an infection is found.
These disorders have similar symptoms, such as, abdominal pain, back pain, blood in the urine, painful urination, frequent and urgent urination.