Ureter

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Ureter
Urinary tract la.png
Ureter (Anatomical View)
Urinary system.svg
Ureter (Schematic View)
1. Human urinary system: 2. Kidney, 3. Renal pelvis, 4. Ureter, 5. Urinary bladder, 6. Urethra. (Left side with frontal section), 7. Adrenal gland
Vessels:
8. Renal artery and vein, 9. Inferior vena cava, 10. Abdominal aorta, 11. Common iliac artery and vein
With transparency:
12. Liver, 13. Large intestine, 14. Pelvis
Details
Precursor Ureteric bud
Artery Superior vesical artery, Vaginal artery, Ureteral branches of renal artery
Identifiers
Latin Ureter
MeSH A05.810.776
Dorlands
/Elsevier		 Ureter
TA A08.2.01.001
FMA 9704
Anatomical terminology

In human anatomy, the ureters are tubes made of smooth muscle fibers that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25–30 cm (10–12 in) long and ~3–4 mm in diameter. Histologically, the ureter contains transitional epithelium and an additional smooth muscle layer in the more distal one-third to assist with peristalsis.

Structure[edit]

In humans, the ureters arise from the pelvis of each kidney, and descend on top of the psoas major muscle to reach the brim of the pelvis. Here, they cross in front of the common iliac arteries. They then pass down along the sides of the pelvis, and finally curve forwards and enter the bladder from its left and right sides at the back of the bladder.[1]:324–326 This is classically depicted as running "posteroinferiorly on the lateral walls of the pelvis and then curve anteromedially to enter the bladder". The orifices of the ureters are placed at the postero-lateral angles of the trigone of the bladder, and are usually slit-like in form. In the contracted bladder they are about 2.5 cm. apart and about the same distance from the internal urethral orifice; in the distended bladder these measurements may be increased to about 5 cm.

The junction between the pelvis of the kidney and the ureters is known as the ureteropelvic junction or ureteral pelvic junction, and the junction between the ureter and the bladder is known as the ureterovesical (ureter-bladder) junction. At the entrance to the bladder, the ureters are surrounded by valves known as ureterovesical valves, which prevent vesicoureteral reflux (backflow of urine).[citation needed]

In females, the ureters pass through the mesometrium and under the uterine arteries on the way to the urinary bladder.

Constrictions[edit]

The ureter has a diameter of 3 mm but there are five constrictions,]:[2]

  • at the ureteropelvic junction of the renal pelvis and the ureter
  • At the brim of lesser pelvis
  • Point of crossing of ureter by ductus deferens or broad ligament of uterus
  • At its opening in lateral angle of trigone
  • During its oblique passage through the bladder wall

Development[edit]

During the embryologic development of the kidney, the ureteropelvic junction is the last part of the ureter to become patent.

Blood supply[edit]

The ureters receive a segmental arterial supply, which varies along its course.[1]:324–326

  1. The upper part of the ureter closest to the kidney is supplied by the renal arteries
  2. The middle part of the ureter is supplied by the common iliac arteries, direct branches from the abdominal aorta, and gonadal arteries (the testicular artery in men or ovarian artery in women)
  3. The lower part of the ureter closest to the bladder is supplied by branches from the internal iliac arteries,[1]:324–326 as well as[citation needed]:
  • Superior vesical artery
  • Uterine artery (in women only)
  • Middle rectal artery
  • Vaginal arteries (in women only)
  • Inferior vesical artery (in men only)

Within the periureteral adventitia these arteries extensively anastomose thus permitting surgical mobilization of the ureter without compromising the vascular supply as long as the adventitia is not stripped. Lymphatic and venous drainage mostly parallels that of the arterial supply.[3]

Nerve supply[edit]

The ureters are richly innervated by nerves that travel alongside the blood vessels, building the ureteric plexus.[4] The primary sensation to the ureters is provided by nerves that come from T12-L2 segments of the spinal cord. Thus pain may be referred to the dermatomes of T12-L2, namely the back and sides of the abdomen, the scrotum (males) or labia majora (females) and upper part of the front of the thigh.[1]:324–326

Histology[edit]

The ureter is surrounded by urothelium, a type of transitional epithelium that is capable of responding to stretches in the ureters. The transitional epithelium may appear as a columnar epithelia when relaxed, and squamous epithelia when distended. Below the epithelium, a Lamina Propria exists. The Lamina Propria is made up of loose connective tissue with many elastic fibers interspersed with blood vessels, veins and lymphatics. The ureter is surrounded by two muscular layers, an inner longitudinal layer of muscle, and an outer circular or spiral layer of muscle.[5]:324

Function[edit]

The ureters are a component of the urinary system. Urine, produced by the kidneys, travels along the ureters to the bladder.

  • Ultrasound demonstration of ureteral jet effect

  • Doppler ultrasound image ureteric jet effect inside urinary bladder.

Clinical significance[edit]

Cancer of the ureters is known as ureteral cancer.

The ureters are also known for being extremely hard to work around during surgery and account for 80 percent of failed kidney transplants.[citation needed]

Failure of the ureteropelvic junction to become patent during development is the most frequent cause of bilateral hydronephrosis, particularly in male neonates. Pyeloplasty, which involves excision of the stenotic section and creation of a new junction, is the most common and effective treatment for this problem.

Injury[edit]

Injuries to the ureter with certain forms of trauma including penetrating abdominal injuries and injuries at high speeds followed by an abrupt stop (e.g., a high speed car accident).[6] The ureter is injured in 0.2 per 1,000 cases of vaginal hysterectomies and 1.3 per 1,000 cases of abdominal hysterectomies,[7] near the infundibulopelvic (suspensory) ligament or where the ureter courses posterior to the uterine vessels.[8]

Kidney stones[edit]

A kidney stone can move from the kidney and become lodged inside the ureter, which can block the flow of urine, as well as cause a sharp cramp in the back, side, or lower abdomen.[9] The affected kidney could then develop hydronephrosis, should a part of the kidney become swollen due to blocked flow of urine.[10] There are three sites where a kidney stone will commonly become stuck:

  • at the ureteric junction of renal pelvis;
  • as the ureter passes over the iliac vessels;
  • where the ureter enters into the urinary bladder (vesicoureteric junction).

Reflux[edit]

Vesicoureteral reflux refers to the reflux of fluid from the bladder to the ureters during urination. This condition can be one cause of chronic urinary tract infections, particularly in children. Vesicoureteral reflux may be treated surgically, and is believed to have a genetic basis.[citation needed]

Other animals[edit]

Ureters are also found in all other amniote species, although different ducts fulfill the same role in amphibians and fish.[11]

References[edit]

  1. ^ a b c d Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN 978-0-8089-2306-0. 
  2. ^ Gai, Dayu. "Dr". Radiopaedia. Dr Dayu Gai. Retrieved 12 June 2016. 
  3. ^ Wein, Alan J. (2011). Campbell-Walsh Urology, 10th. ed. Elsevier. p. 31. 
  4. ^ Dudeck, Ronald W. (2007). High-yield kidney. High-yield systems (1 ed.). Lippincott Willams and Wilkins. p. 19. ISBN 978-0-7817-5569-6. 
  5. ^ Lowe, Alan Stevens, James S. (2005). Human histology (3rd ed.). Philadelphia, Toronto: Elsevier Mosby. ISBN 0-3230-3663-5. 
  6. ^ Stein DM, Santucci RA (July 2015). "An update on urotrauma". Current opinion in urology. 25 (4): 323–30. doi:10.1097/MOU.0000000000000184. PMID 26049876. 
  7. ^ Burks FN, Santucci RA (June 2014). "Management of iatrogenic ureteral injury". Ther Adv Urol. 6 (3): 115–24. doi:10.1177/1756287214526767. PMC 4003841Freely accessible. PMID 24883109. 
  8. ^ Santucci, Richard A. "Ureteral Trauma". Medscape. Retrieved 11 April 2012. 
  9. ^ "Symptoms of Kidney Stones". MedicalBug. 1 January 2012. Retrieved 11 April 2012. 
  10. ^ Resnick, Martin I; Lam, Mildred; Zipp, Thomas (4 September 2009). "Kidney Stones". NetWellness. Retrieved 11 April 2012. 
  11. ^ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 378. ISBN 0-03-910284-X. 

External links[edit]

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