Understanding the Ureters
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Ureters are essential muscular tubes that transport urine from the kidneys to the bladder. [1] By using rhythmic contractions, they ensure the efficient removal of liquid waste from the body. Conditions such as obstructions, stones, and infections can affect their function, often leading to pain and changes in urination habits. [1]
Quick Answer
Ureters are two narrow, muscle-lined tubes in the urinary system. [1] Their primary function is to carry urine produced in the kidneys down to the urinary bladder for storage. [1] Through rhythmic muscle contractions known as peristaltic waves, the ureters actively propel liquid waste, maintaining a one-way flow that protects the kidneys from backflow and potential infection.
What the research says
Drinking more fluid lowers the risk of kidney stones. A meta-analysis of 9 studies (2 randomized trials with 269 patients and 7 observational studies with 273,685 people) found pooled relative risks of kidney stones with high versus inadequate fluid intake of 0.40 (95% CI 0.20-0.79) in the trials and 0.49 (95% CI 0.34-0.71) in the observational studies; for recurrent stones the relative risk in the trials was 0.40 (95% CI 0.20-0.79) (Cheungpasitporn et al., Journal of Nephrology, 2016) [2].
Alpha-blocker medicines can help small ureteral stones pass. In a meta-analysis of 14 randomized trials of stones under 1 cm, silodosin produced a higher stone expulsion rate than tamsulosin (odds ratio 2.42; 95% CI 1.91-3.06), with no significant difference in total complications (Jung et al., Medicina, 2022) [3].
In children with reflux, preventive antibiotics reduce infections but raise resistance. Across 8 trials, continuous antibiotic prophylaxis in children with vesicoureteral reflux reduced recurrent febrile or symptomatic urinary tract infection (pooled odds ratio 0.63; 95% CI 0.42-0.96), but increased the odds of antibiotic-resistant infection (8.75; 95% CI 3.52-21.73) and did not significantly reduce new renal scarring (Wang et al., The Journal of Urology, 2015) [4].
Anatomy of the Ureters
The ureters are located in the abdominal and pelvic regions, connecting the kidneys to the bladder. [1] Each adult typically has two ureters, measuring between 10 and 12 inches in length. [1]
Feature | Description |
Location | Extend from the renal pelvis in the kidneys to the sides of the bladder. [1] |
Dimensions | 10-12 inches (25-30 cm) long; 0.1-0.15 inches (3-4 mm) in diameter. [1] |
Outer Layer | Adventitia: Strong connective tissue with nerves and blood supply. [1] |
Middle Layer | Muscularis: Smooth muscle sheets that propel urine. [1] |
Inner Layer | Mucosa: Epithelium that secretes protective mucus. [1] |
Function and Movement
The primary role of the ureters is the active transport of urine. Unlike a simple drain pipe, the ureters use muscular power to move liquid. The smooth muscle layer of the ureteral wall contracts in rhythmic waves, pushing urine toward the bladder even when a person is lying down. This active movement ensures that waste does not accumulate in the kidneys, which could lead to pressure and damage.
Key functional steps include:
Kidneys produce urine as a byproduct of blood filtration.
Ureters receive urine at the renal pelvis.
Muscular contractions propel urine in waves. [1]
Urine enters the bladder through the ureteral openings.
Common Ureteral Conditions
When the flow of urine through the ureters is disrupted, it can lead to significant discomfort and health risks. Obstructions and infections are among the most frequent issues encountered.
Ureteral Obstruction: A blockage caused by scar tissue, blood clots, or an enlarged prostate that prevents urine from reaching the bladder. [1]
Ureteral Stones: Kidney stones that become lodged in the narrow passage of the ureter, often causing severe flank pain.
Vesicoureteral Reflux (VUR): A condition where urine flows backward from the bladder toward the kidneys, increasing the risk of infection.
Congenital Abnormalities: Conditions present at birth, such as an ectopic ureter (misconnected tube) or a ureterocele (bulging at the bladder connection). [1]
Infections: Bacteria can travel up the ureters from the bladder, potentially leading to a kidney infection (pyelonephritis). [1]
Symptoms often include abdominal or pelvic pain, fever, nausea, and changes in urine appearance, such as cloudiness or the presence of blood. Get emergency care right away if severe flank pain comes with fever or chills, or if you cannot pass urine, because a blocked, infected kidney is an emergency. [1]
Caring for Ureteral Health
Maintaining a healthy urinary system is the best way to protect the ureters. Proper hydration is a key strategy, as it helps prevent the formation of stones and flushes bacteria out of the system.
Conclusion
The ureters are vital conduits that ensure the safe and efficient removal of liquid waste from the body. By actively transporting urine from the kidneys to the bladder, they play a key role in maintaining internal balance and protecting renal health. Through hydration and proactive medical care, individuals can support the long-term function of these essential muscular tubes.
Frequently Asked Questions
What are ureters?
Ureters are narrow, muscle-lined tubes that carry urine from the kidneys to the urinary bladder.
How many ureters does a person have?
Most people have two ureters, one connecting each kidney to the bladder.
How long are the ureters?
In most adults, the ureters are between 10 and 12 inches (25 to 30 centimeters) long.
What is the function of the ureters?
The ureters' primary function is to propel urine into the bladder through rhythmic muscular contractions.
What are ureteral stones?
Ureteral stones are urinary stones that form in the kidneys and become stuck in the ureter.
What is a ureteral obstruction?
A ureteral obstruction is a blockage in one or both ureters that prevents the normal flow of urine.
What are the symptoms of a ureter problem?
Common symptoms include abdominal or flank pain, fever, nausea, and blood in the urine.
Can a damaged ureter be repaired?
Yes, treatments range from medications and stents to surgical procedures, depending on the cause of the damage.
What is vesicoureteral reflux?
Vesicoureteral reflux is a condition where urine flows backward from the bladder into the ureters and kidneys.
How can I prevent ureteral stones?
Staying well-hydrated is one of the most effective ways to help prevent the formation of urinary stones.
Related Reading
Ureterostomy: Purpose, Procedure, Care and Recovery explains ureterostomy.
References
Cleveland Clinic. Ureters. Cleveland Clinic. Last updated May 21, 2025. https://my.clevelandclinic.org/health/body/ureters
Cheungpasitporn W, Rossetti S, Friend K, et al. Treatment effect, adherence, and safety of high fluid intake for the prevention of incident and recurrent kidney stones: a systematic review and meta-analysis. Journal of Nephrology. 2016;29(2):211-219. PMID 26022722. https://doi.org/10.1007/s40620-015-0210-4
Jung HD, Cho KS, Jun DY, et al. Silodosin versus tamsulosin for medical expulsive therapy of ureteral stones: an updated systematic review and meta-analysis of randomized controlled trials. Medicina (Kaunas). 2022;58(12):1794. PMID 36556996. https://doi.org/10.3390/medicina58121794
Wang HS, Gbadegesin RA, Foreman JW, et al. Efficacy of antibiotic prophylaxis in children with vesicoureteral reflux: systematic review and meta-analysis. The Journal of Urology. 2015;193(3):963-969. PMID 25196653. https://doi.org/10.1016/j.juro.2014.08.112
Medical disclaimer
The information provided in this article is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
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