Ureter

Ureter

Ureter (Anatomical View)

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

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 junction between the pelvis of the kidney and the ureters is known as the pelvoureteric junction and the junction between the ureter and the bladder as the vesicoureteric junction. At the entrance to the bladder, the ureters are surrounded by valves known as ureterovesical valves, which prevent the backflow of urine.

In females, the ureters pass through the mesometrium and under the uterine arteries on the way to the urinary bladder. An effective phrase for remembering this anatomical relationship is "water (ureters) under the bridge (uterine arteries or vas deferens).

Blood supply

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:
  • 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.[2]

Innervation

The ureters are richly innervated by nerves that travel alongside the blood vessels, building the ureteric plexus.[3] 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

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.[4]:324

In other animals

Ureters are also found in all other amniote species, although different ducts fulfill the same role in amphibians and fish.[5]

Function

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

Clinical significance

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.

Injury

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

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:

Reflux

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.

References

  1. 1 2 3 4 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. ↑ Wein, Alan J. (2011). Campbell-Walsh Urology, 10th. ed. Elsevier. p. 31.
  3. ↑ Dudeck, Ronald W. (2007). High-yield kidney. High-yield systems (1 ed.). Lippincott Willams and Wilkins. p. 19. ISBN 978-0-7817-5569-6.
  4. ↑ Lowe, Alan Stevens, James S. (2005). Human histology (3rd ed.). Philadelphia, Toronto: Elsevier Mosby. ISBN 0-3230-3663-5.
  5. ↑ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 378. ISBN 0-03-910284-X.
  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 4003841. 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.

External links

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