The ureters are muscular tubes that form a part of the urinary system. Most people have two of these tubes, with one connected to each kidney. Their purpose is to carry urine, which is produced by the kidneys as they filter waste from the blood, to the bladder for storage.
Anatomy and Function of the Ureters
In the average adult, each ureter is a narrow tube measuring approximately 10 to 12 inches in length. One ureter descends from each kidney, with the upper portion residing in the abdomen and the lower half extending into the pelvic area before connecting to the bladder. The walls of the ureters are composed of smooth muscle, which gives them the ability to contract and move urine.
The transportation of urine from the kidneys to the bladder is not a passive process reliant on gravity. Instead, the ureters employ a mechanism called peristalsis, which involves rhythmic, wave-like contractions of the muscular walls. These involuntary contractions actively propel the urine downward through the ureter and into the bladder, ensuring a constant, one-way flow away from the kidneys.
Common Medical Conditions
Ureters can be affected by several medical issues that disrupt normal urinary function. The most frequent problem is the presence of ureteral stones, which are kidney stones that have traveled from the kidney and become lodged within the narrow ureter. This can obstruct the flow of urine and cause significant pain.
Another common condition is a ureteral obstruction or stricture, which is a blockage or narrowing of the tube. This can be caused by the buildup of scar tissue from past infections, surgery, or the passage of a kidney stone. In some cases, congenital abnormalities, meaning issues present from birth, or pressure from external growths can also lead to a narrowing of the ureter.
Vesicoureteral reflux (VUR) primarily affects children. In this condition, the valve-like mechanism where the ureter joins the bladder is faulty, allowing urine to flow backward from the bladder up into the ureters. This reverse flow can increase the risk of urinary tract infections and lead to potential kidney damage over time if not addressed.
Symptoms of Ureteral Problems
Pain is one of the most common indicators, particularly with ureteral stones. This pain, often called renal colic, is typically severe and spasmodic, felt in the flank or side and frequently radiating down toward the groin. The pain comes in waves as the ureter contracts around the lodged stone.
Changes in urination are also a frequent sign. The presence of blood in the urine, a condition known as hematuria, can occur when a stone scrapes the lining of the ureter. Individuals may also experience a frequent or urgent need to urinate, or pain during urination. In cases of a significant blockage, the urine might appear cloudy or have a foul smell, suggesting a possible infection.
If a blockage in the ureter is severe and persistent, it can lead to more systemic symptoms. When urine cannot drain properly from the kidney, it can cause a backup of pressure and may lead to an infection in the kidney itself, a condition called pyelonephritis. This can result in symptoms like fever, nausea, and vomiting, signaling a more serious complication that requires prompt medical attention.