Ureter
From Wikipedia, the free encyclopedia
| Ureter | |||
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| Gray's | subject #254 1225 | ||
| Artery | Superior vesical artery, Vaginal artery, Ureteral branches of renal artery | ||
| Precursor | Ureteric bud | ||
| MeSH | Ureter | ||
| Dorlands/Elsevier | u_03/12838140 | ||
In human anatomy, the ureters are muscular ducts that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25-30cm (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.
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[edit] 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.
[edit] 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.
[edit] External links
- SUNY Labs 40:06-0111 - "Posterior Abdominal Wall: Internal Structure of a Kidney"
- SUNY Figs 43:08-02 - "Relationship of the ureter to the uterine artery."
- SUNY Figs 44:02-01 - "Mid-sagittal section of male pelvis."
- SUNY Anatomy Image 8923
- SUNY Anatomy Image 8945
- Virtual Slidebox at Univ. Iowa Slide 444
- Organology at UC Davis Urinary/mammal/ureter/ureter1 - "Mammal, ureter (LM, Medium)"
- Histology at KUMC urinary-renal15 - "Ureter"
- Cross section at UV pelvis/pelvis-female-17
[edit] Additional images
 Bladder |
 Frontal section through the kidney |
 Wall of the ureter. |
 Transverse section of human embryo eight and a half to nine weeks old. |
 Tail end of human embryo thirty-two to thirty-three days old. |
 The relations of the viscera and large vessels of the abdomen. (Seen from behind, the last thoracic vertebra being well raised.) |
 The posterior surfaces of the kidneys, showing areas of relation to the parietes. |
 Vertical section of kidney. |
 Transverse section of ureter. |
 The interior of bladder. |
 Fundus of the bladder with the vesiculæ seminales. |
 Median sagittal section of male pelvis. |
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