Anatomy of the Ureters

Ureters are the tubes that transport urine from the kidneys to the bladder. There are two ureters in the human body, one connected to each kidney. Ureteral tubes are made of smooth muscle that contracts to push urine from the kidneys to the bladder.

Ureters can get blocked and infected. Left untreated, conditions of the ureters can lead to kidney damage.

Anatomy

Ureters connect the kidneys to the bladder. The upper half of each ureter is located in the abdomen and the lower half is in the pelvis. They are approximately 20 to 30 centimeters long in adults.

There are two ureters, one connected to each kidney. The kidneys are situated below the ribs, toward the middle of the back. The ureters each run to the bladder, a hollow, muscular organ located in the pelvis. Ligaments, connected to other organs and bones, hold the bladder in place.

The wall of the ureter has three layers: the outer layer, made of fibrous connective tissue; the middle layer, made of smooth muscle; and a moist, inner lining that protects the surface of the cells.

Anatomical Variations

Duplicate ureters, also called duplex kidney, is the most common renal abnormality. It develops in utero, resulting in two ureters stemming from a single kidney. Duplicate ureters can be complete or incomplete.

Complete duplicates have two separate ureters that leave the kidney and enter the bladder separately. Incomplete duplicates join together at some point and enter the bladder as a single tube.

An ectopic ureter is an abnormality where the ureter does not enter the bladder in the correct position or sometimes it does not connect with the bladder at all.

If the ureter does not connect to the bladder, it may instead drain into the urethra, vagina, or prostate. Often people with ectopic ureters experience urinary incontinence since the urine bypasses the bladder.

Ureterocele is a congenital anomaly characterized by the swelling of the ureter as it enters the bladder. Ureteroceles can result in urine flowing backward into the kidney. It can be surgically repaired.

Function 

The ureters are the part of the urinary system, whose function is to filter blood and create urine as a waste product. The ureters’ role in the process is to carry urine from the kidneys to the bladder. 

Contractions in the ureter force urine away from the kidneys and into the bladder. The ureters work constantly, emptying urine into the bladder about every 10 to 15 seconds.

In addition to their role in eliminating waste from the body, the kidneys also balance fluids in the body, release hormones to regulate blood pressure, and control the production of red blood cells. 

Like the ureters, the bladder is a muscular organ that contracts to eliminate urine. The average adult bladder can hold up to about 2 cups of urine.

Associated Conditions 

Uretal conditions can be congenital or a result of injury or infection. Ureter problems occur when the flow of urine from the kidney to the bladder is affected. If urine can not move out of the kidneys, a kidney infection can develop. 

Ureteral Obstruction

Ureteral obstructions are blockages in the ureter. Left untreated, an obstruction can cause damage to the kidneys.

Causes of obstruction include:

• Enlarged prostate
• Kidney stones
• Scarring
• Tumors
• Pregnancy
• Blood disorders and blood clots
• Ureteral stones
• Congenital abnormalities

Symptoms of a blocked ureter include pain in the side or abdomen, blood in urine, nausea, leg swelling, and reduced urine output. Treatment for an obstructed ureter may involve antibiotics to clear an infection, drainage, and surgery.

Ureter Stones 

Ureter stones are kidney stones that travel through the ureter. Kidney stones form when waste builds up and sticks together in your kidneys. Sometimes stones are small enough to pass through the ureter; other times, they are too large and they get stuck.

If a ureter stone is small, you may have no notable symptoms. If, however, it is large and becomes stuck, you may notice some of the following:

• Painful urination
• Cramping in the lower abdomen and groin
• Blood in urine
• Burning sensation while urinating

Sometimes ureteral stones can lead to an infection. If an infection is present, you may have a fever and chills.

Treatment for ureter stones involves drinking lots of fluids. This helps the stone naturally pass out of the body on its own. If the stone causes a lot of pain, your healthcare provider may prescribe pain medication. If there is an infection, your practitioner will prescribe antibiotics.

If the stone is stuck, surgery may be necessary. Your healthcare provider may also use less invasive procedures, like shock waves to break up the stone, stents to allow a larger opening for the stone to pass through, or medication to help the stone pass.

Ureteral Stricture 

Ureteral stricture is the narrowing of the ureter that causes an obstruction of urine. Stricture can cause a backup of urine into the kidneys and can result in kidney infection or damage.

Ureteral stricture can be caused by injury to the ureter, kidney stones, urinary tract infections (UTIs), and tumors. Stricture usually results from a build-up of scar tissue.

Symptoms include pain in the abdomen or side, blood in the urine, difficulty urinating, nausea, and urinary tract infections. Treatment may include surgery, endoscopy, percutaneous nephrostomy, or a stent.

Ureteral Cancer

Ureteral cancer is cancer that forms in the ureter. Ureteral cancer is uncommon. It affects mostly older people and people assigned male at birth. Having ureteral cancer puts you at increased risk for bladder cancer. 

Symptoms of ureteral cancer may include back pain, pain along the ribs, blood in the urine, pain while urinating, weight loss, and fatigue. Treatment depends on how advanced the cancer is, but may involve removal of the tumor and surrounding organs, radiation, and chemotherapy. 

Vesicoureteral Reflux

Vesicoureteral reflux (VUR) is characterized by urine flowing backward, out of the bladder, through the ureter and back into the kidney. Untreated, it can result in damage to the kidney and high blood pressure.

The most common symptom of VUR is recurring urinary tract infections (UTIs). Other symptoms include incontinence, diarrhea, constipation, nausea, vomiting, and poor weight gain in infants.

VUR may be caused by a congenital defect (called primary VUR) or by a blockage of the bladder or ureter or nerve problems (called secondary VUR). If VUR is caused by a congenital abnormality, a child may outgrow it over time.

Antibiotics will be prescribed to treat acute UTIs. If the VUR is secondary, your healthcare provider may perform surgery or use a catheter to treat the underlying issue. 

Urinary Tract Infection

Urinary tract infections can affect any part of your urinary tract, inlcuding ureters. The most common part of the urinary system affected by UTIs is the bladder. UTIs occur when bacteria enter the urethra and infect the urinary tract.

Symptoms of UTIs are pain and burning while urinating, frequent urination, or feeling the need to urinate, even when your bladder is empty. UTIs are treated with antibiotics.

Tests 

If you are experiencing symptoms that may indicate a condition of the ureter, your healthcare provider may run tests. Tests will likely include scans to look a the ureter and surrounding organs.

Common tests include:

• Blood and urine tests to check for signs of infection
• Ultrasound to observe the organ and any growth or obstruction
• Computerized tomography (CT) scan to observe the organ and any growth or obstruction
• Magnetic resonance imaging (MRI) to observe the organ and any growth or obstruction
• Voiding cystourethrogram to see how the urinary tract functions
• Renal nuclear scan to see how your kidneys function