ureter


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ureter

(yo͝orē`tər), thick-walled tube that conveys urine from the kidneykidney, artificial,
mechanical device capable of assuming the functions ordinarily performed by the kidneys. In treating cases of kidney failure a tube is inserted into an artery in the patient's arm and blood is channeled through semipermeable tubes immersed in a bath
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 to the urinary bladder. It is approximately 10 in. (25.4 cm) long, with the upper half located in the abdomen and the lower half in the pelvic region. Urine is transported down this tube under the impetus of gravity assisted by contractions of the smooth muscles that line the ureteral walls. A blocked ureter can result from congenital abnormality, a tumor, or the formation of kidney stones. Blockage may require surgery to prevent loss of urinary function and eventual urea poisoning. See urinary systemurinary system,
group of organs of the body concerned with excretion of urine, that is, water and the waste products of metabolism. In humans, the kidneys are two small organs situated near the vertebral column at the small of the back, the left lying somewhat higher than the
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.

Ureter

 

the efferent duct that serves to remove the urine from the kidney.

During the embryonic development of many vertebrates, the excretory function is fulfilled by three successive forms of kidney: the pronephros (also called the primordial kidney or the forekidney), the mesonephros (also called the middle kidney), and the metanephros—the definitive, permanent kidney. Correspondingly, three types of ureter arise: the pronephric duct, the mesonephric duct (also called Wolffian duct), and the metanephric duct—the definitive, permanent ureter.

The pronephric ducts continue to function past the embryonic stage only in cyclostomes, in which the ducts open into the urogenital sinus. In fish and amphibians, the Wolffian ducts continue to function as ureters throughout postembryonic life. In certain fish—dipnoans, chondrosteans, and holosteans—and in male amphibians, the ureters also function as the deferent ducts. The mesonephric ducts of fish open to the exterior of the body either directly through the urinary orifice (in all female teleosts and in the males of a few teleost species), through the urogenital sinus (in elasmobranchs, holocephalans, chondrosteans, holosteans, Polypterus, and most male teleosts), or through the cloaca (in chondrichthians and dipnoans). In most teleosts, the ureters empty into the urinary bladder. The metanephric ducts are the postembryonic ureters of reptiles, birds, mammals, and man; in all these, the sole function of the ureter is to conduct urine. In birds, monotremes, and most reptiles, the ureters empty into the cloaca, while in metatherians, viviparous mammals, certain reptiles, and man, they empty into the urinary bladder.

In man the two ureters are tubular organs through which urine flows from the kidneys into the urinary bladder. The ureters are situated on the posterior wall of the abdominal cavity on both sides of the spinal column. On the average, each ureter is 30–35 cm long and 7–9 mm at its widest diameter. The ureters are internally lined with mucosa. Smooth muscles in the walls of the ureters ensure the flow of urine to the urinary bladder, regardless of the position the body is in.

Urethritis—inflammation of the ureteral mucosa—is the commonest disease of the ureters. Kidney stones can pass through the ureters, causing injury to the ureteral linings. Occasionally, one or both ureters can be congenitally bifurcated at the site of emergence from the kidney; complete doubling of one or both ureters is also possible. Other developmental anomalies include prolapse of the ureter into the vagina (in women) or into the seminal vesicles (in men).

ureter

[′yu̇r·əd·ər]
(anatomy)
A long tube conveying urine from the renal pelvis to the urinary bladder or cloaca in vertebrates.

ureter

the tube that conveys urine from the kidney to the urinary bladder or cloaca
References in periodicals archive ?
A new catheter-based system specifically for female cystoscopy and simple diagnostic visualization of the female bladder and ureters is now available.
36%) patients in Group II due to the inability to reach the stone, impacted stones, severe ureteral stricture, tortuous, kinked, or angulated ureter, ureteral perforation or avulsion, or technical problems.
Cancer of the ureter begins in the cells that line the inside of the ureters that connect kidneys to bladder.
The lithotripsy unit is supported by many other departments in the hospital, particularly the laboratory, radiology, and internal medicine," explains Professor Rajaie Mahran, Consultant Urologist, University Hospital in Sharjah that recently launched the unit to treat kidney, bladder and ureter stones without surgical interference.
Conclusion: In patients with a low-capacity, poorly compliant bladder, augmentation cystoplasty using the ureter seems to flea viable alternative.
We retrospectively reviewed procedural and pathology reports for endoscopic biopsies of the ureter, renal pelvis, or ureteropelvic junction from January 2008 to December 2011 at The Ohio State University Medical Center (Columbus, Ohio).
Fibroepithelial polyps are benign mesodermal tumors of the ureter composed of a fibrovascular core lined by normal urothelium.
In children who have reflux, the valve does not work properly and urine flows out of the bladder back up the ureter to the kidney.
Instead Mr Cooper has been left with two small 'port hole' scars on his back where the instruments and camera were inserted to enable to surgery to take place and a small seven centimetre scar on the front of his abdomen where the diseased ureter and kidney were removed.
Among those aimed at the restoration of urodynamics, the most frequently used is the Anderson-Hynes operation which involves the resection of pathologically formed pyeloureteral segment and creation of anastomosis between the pelvis and ureter.
Aspartame-fed females showed significant evidence of lymphomas/leukemias and of carcinomas of the renal pelvis and ureter.
Kidney stones cause severe pain, especially if these stones become trapped in the ureter.