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Ureter
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
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 the ducts that carry urine from the kidneys to the urinary bladder, passing anterior to the psoas major. The ureters are muscular tubes that can propel urine along by the motions of peristalsis. In the adult, the ureters are usually 25-30cm long.

In humans, the ureters enter the bladder through the back, running within the wall of the bladder for a few centimetres. 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.

Cross section through a microscope.

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.

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.

Medical problems that can affect the ureter include:

• cancer of the ureter
• passage of kidney stones
• ureterocele
• megaureter
• vesico-ureteric reflux
• anatomical abnormalities, such as duplexing and ectopia.

• 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

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.
Kidneys viewed from behind with spine removed