Synonyms
Medical: Ureter
- Urinary tract
- Uringang
- Kidney
- Bubble
Anatomy
The ureter connects the renal pelvis (Pelvis renalis), which collects urine from the kidney like a funnel, with the bladder. The ureter is an approximately 30-35 cm long tube consisting of fine muscles with a diameter of about 7 mm. It runs behind the abdominal cavity (abdomen) on the inner back muscles down to the pelvis, where it reaches the bladder from behind.
The right ureter is a little shorter, because the right kidney is a little lower due to the space-consuming expansion of the liver. The ureter opens into the bladder at an angle, which is favourable for the closure of the ureter, because it is compressed by the strong muscles of the bladder, so that, for example when lying down, no urine can flow back into the ureter. In addition to this constriction at the end of the ureter, two more occur on the way to the bladder.
The transition from the renal pelvis to the ureter shows a narrowing, and the clearing of the ureter is also reduced by the large blood vessels in the pelvis when the ureter enters the pelvis. These three narrowings can play an important role if there are stones (kidney stones) in the ureter, which can then get stuck (see below). In the pelvis, the ureter is adjacent to the cervix (cervix uteri) in women and the spermatic duct (ductus deferens) in men.
Function
In addition to its function as a link between the kidney and the bladder, the ureter also has an important task in transporting the urine. When lying down, gravity counteracts the flow of urine. The ureter can gradually tense its muscles, so that the urine reaches the bladder against the slope, just like on a conveyor belt.
This tensing up is called peristaltic wave. It runs 1-4 times per minute over the ureter. The principle is similar to that of the esophagus, which also transports food to the stomach when standing on its head.
Men and women are equally affected by kidney stones. The risk of developing a stone in the kidney increases with age. Stress can have an unfavorable effect on the occurrence of urinary calculus kidney stones.
The climate can also have an influence on the development of kidney stones. The more water is lost through sweating, the more concentrated the urine is. If the urine is too concentrated or certain substances are present in abundance, possibly due to incorrect nutrition or certain congenital disorders in the breakdown of waste products of the body, the probability of urinary stones is greatly increased because these substances can no longer dissolve in the urine and precipitate as crystals.
The so-called pH value, i.e. the acidity of the urine, plays an important role in this process. Depending on how much acid is present, some stones develop more easily. An inflammation in the urinary tract or if the urine flow is disturbed, for example by congenital malformations, can also promote the formation of urinary stones.
Normally the body produces substances that inhibit the formation of stones. If there is too little of them, urinary stones can form more easily. Different stones can be distinguished based on their composition and origin.
On the one hand, urinary stones can develop in the renal pelvis (Pelvis renalis) anchored to the wall. These are called calyx stones or fixed stones. They can come loose and be washed into the urinary tract, i.e. into the ureter.
On the other hand, uric acid and cystine stones form freely in the urine, simply because the concentration of these substances is too high or because the pH value of the urine has changed. They can form anywhere in the urinary tract. Most stones (70%) consist of calcium oxalate, if there is too much calcium or oxalate in the urine or if there are too few substances that inhibit stone formation.
Uric acid stones (10-15%) are formed when purine accumulates. Purine is a breakdown product of, for example, DNA, which we ingest in large quantities when we eat meat. When the breakdown is disturbed, possibly due to a congenital defect, or when the kidney is damaged or overtaxed due to an excessive intake of meat and alcohol, these stones are formed.
Calcium and magnesium phosphate stones (5-10%) are so-called infectious stones, which are formed when bacteria change the pH value of the urine through their waste products during inflammation.Cystine stones are rare (1-2%) and consist mainly of the protein component cystine. They are usually formed due to a hereditary enzyme deficiency. Xanthine stones and other stones make up less than 0.5% of all kidney stones.
People with urinary stones become aware of the stones mainly when they are in the ureter and cause pain due to the stretching of the ureteral wall. These pains are usually colicky (i.e. they come and go in the form of waves) with an undulating spread into the flanks, the bladder or even the scrotum (scrotum) in men or the labia majora (labia majora) in women. In addition, an unrelievable urge to urinate can occur due to possibly congested urine.
If the urinary retention continues, this can lead to inflammation or blood poisoning with urinary substances that cannot be excreted (urosepsis). Ureteral calculi (ureteral stones) can be detected mainly by imaging procedures such as ultrasound or contrast medium examinations (intavenous urogram). In ultrasound, stones larger than 2 mm can be detected.
But urine examination can also provide an indication in the presence of blood or small urinary stone crystals. Depending on the detected crystals and the pH value, conclusions can also be drawn as to the cause. A blood test can also be revealing if so-called urinary substances such as creatinine are present in large quantities.
Since 70-80% of the stones come off spontaneously because they are driven by the peristaltic wave of the ureter described above, it is usually possible to treat them with an antispasmodic agent such as Buscopan® and painkillers. Uric acid stones, which are sometimes formed due to the acid content, can be treated with alkalizing drugs which neutralize the urine a little and thus dissolve the stones, e.g. Uralyt U (the salt of citric acid). If the stones cannot be treated with medication, one can resort to so-called endourological measures, which are characterized by passing a special catheter through the ureter past the stone and draining the urine.
The stone is usually pushed back into the renal pelvis, where it is easier to break it up (see below). Stones can be shattered from the outside by a special technique using certain radio waves or electromagnetic waves without having to intervene directly in the body (extracorporeal shock wave lithotripsy). No general anesthesia is required and the small debris can be easily excreted through the ureter and bladder.
In the case of very persistent or large stones, additional invasive access to the stone must be made through the skin (percutaneous nephrolitholapaxy). Since ureteral stones (ureteral stones) are particularly difficult to localize, they are usually treated endoscopically under anesthesia. This means that a tube equipped with a camera is inserted through the urethra (urethra) and the bladder (vesica urinaria) into the ureter and the stone can then be precisely removed with the help of the image.
You can prevent the formation of urinary stones if you adjust your diet accordingly, exercise a lot and drink plenty of fluids. You can also take magnesium and citrate to inhibit the formation of stones. In the case of infectious stones, L-methionine, a protein component, is often added to acidify the urine.
The ureter can be affected as part of a urinary tract inflammation caused by the rise of bacteria through the urethra into the bladder. The development can be promoted by urinary stones. Treatment is given with antibiotics such as timethoprim and sulfamethoxazole (e.g.
CotrimCotrim forte) or amoxillin, cephalosprorins or gyrase inhibitors (e.g. Ciprobay or Tavanic). As with the urinary bladder, the cell layer lining the ureter can degenerate. In the ureter this happens much less frequently.
The suspicion can be confirmed by endoscopic and tissue (histological) examinations. Then a part of the kidney and the ureter with parts of the bladder are surgically removed. Depending on the type of cancer, chemotherapy may also be indicated.
Radiation therapy is usually not used. However, each form of therapy is tailored to the individual situation of the patient.