Ureter

Infobox Anatomy
Name = PAGENAME
Latin =
GraySubject = 254
GrayPage = 1225

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1. Renal pyramid 2. Efferent artery 3. Renal artery 4. Renal vein 5. Renal hilum 6. Renal pelvis 7. Ureter 8. Minor calyx 9. Renal capsule

10. Inferior renal capsule 11. Superior renal capsule 12. Afferent vein 13. Nephron 14. Minor calyx 15. Major calyx 16. Renal papilla 17. Renal column

Precursor = Ureteric bud
System =
Artery = Superior vesical artery, Vaginal artery, Ureteral branches of renal artery
Vein =
Nerve =
Lymph =
MeshName = Ureter
MeshNumber = A05.810.776
DorlandsPre = u_03
DorlandsSuf = 12838140In human anatomy, the ureters are muscular ducts that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25-30 cm (10-12 inches) long.

In humans, the ureters arise from the renal pelvis on the medial aspect of each kidney before descending towards the bladder on the front of the psoas major muscle. The ureters cross the pelvic brim near the bifurcation of the iliac arteries (which they run over). This "pelviureteric junction" is a common site for the impaction of kidney stones (the other being the ureterovesical valve). The ureters run posteroinferiorly on the lateral walls of the pelvis. They then curve anteriormedially to enter the bladder through the back, at the vesicoureteric junction, running within the wall of the bladder for a few centimeters. The backflow of urine is prevented by valves known as ureterovesical valves, pressure from the filling of the bladder, and the tone of the muscle in the bladder wall.

In the female, the ureters pass through the mesometrium on the way to the urinary bladder.

Histology

The ureter has a diameter of about 3 millimeters, and the lumen is star-shaped. Like the bladder, it is lined with transitional epithelium, and contains layers of smooth muscle, thereby being under autonomic control.

The epithelial cells of the ureter are stratified (in many layers), are normally round in shape but become squamous (flat) when stretched. The lamina propria is thick and elastic (as it is important that it is impermeable).

There are two spiral layers of smooth muscle in the ureter wall, an inner loose spiral, and an outer tight spiral. The inner loose spiral is sometimes described as "longitudinal", and the outer as "circular", (this is the opposite to the situation in the gastrointestinal tract). The distal third of the ureter contains another layer of outer longitudinal muscle.

The adventitia of the ureter, like elsewhere is composed of fibrous connective tissue, that binds it to adjacent tissues.

Diseases and disorders

Medical problems that can affect the ureter include:
* cancer of the ureter
* passage of kidney stones - especially at the uteropelvic junctions, where they cross the iliac vessels and their entrance to the bladder.
* ureterocele
* megaureter
* vesico-ureteric reflux
* anatomical abnormalities, such as duplexing and ectopia.

External links

* - "Posterior Abdominal Wall: Internal Structure of a Kidney"
* - "Relationship of the ureter to the uterine artery."
* - "Mid-sagittal section of male pelvis."
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* - "Mammal, ureter (LM, Medium)"
* - "Ureter"
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