The kidneys produce urine (or urine), which is necessary for the water balance and the elimination of toxins. This is then transported away and excreted via the urinary tract. The urinary tract consists of the renal pelvis, the ureters, the bladder and the urethra.
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Article overview
Function of the urinary tract
Urine is produced by the kidneys and is primarily used to remove toxins and other harmful particles from the body. The kidneys also regulate the body's water balance via the urine, which is important for many bodily functions.
The urinary tract, which originates from the kidneys, transports the urine, collects it temporarily and finally excretes it in a controlled manner.
The location of the kidneys and urinary tract in the human body © Sebastian Kaulitzki / Fotolia
Structure of the urinary tract
The kidneys are located above the waist to the left and right of the spine. They have a bean-like shape and have a cavity inside. This contains the renal pelvis, which has a funnel-like structure and collects the urine.
The renal pelvis is connected to the ureters, which in turn lead to the bladder. The kidneys continuously release urine through the ureters. The bladder stores it and ensures that the urine can later be excreted voluntarily. It is very flexible and sphincter muscles ensure that no urine can escape.
Finally, urine is emptied via the urethra, which leads from the bladder to the outside. This is structured very differently in men and women:
- In women, the urethra is only three to five centimetres long and leads from the bladder directly to the vaginal vestibule. It ends in a small opening between the clitoris and the entrance to the vagina.
- The urethra in men is significantly longer (20 to 25 centimeters). It runs through the penis to the glans and fulfills other functions in addition to urination: The seminal ducts flow into the urethra so that it also serves as a seminal duct. However, both tasks only take place at different times: Urine and semen cannot be excreted at the same time. In contrast to the female urethra, the male urethra has several bends and constrictions.
The entire urinary tract is lined with a special tissue, the urothelium. The individual cells of the urothelium lie on top of each other like scales, so that it can expand and contract very strongly.
The urinary tract. 1: Kidney. 2: Renal pelvis. 3: Ureter. 4: Bladder. 5: Urethra
Common diseases of the urinary tract
Inflammations
Urinary tract infections (also known as cystitis ) are among the most common diseases of the urinary tract. As women have a much shorter urethra, they are affected by urinary tract infections much more frequently than men.
They are triggered by bacteria, fungi, viruses or other pathogens. An infection with the body's own intestinal bacteria is very common.
Symptoms of a urinary tract infection are pain and burning when urinating, frequent urge to urinate and abdominal pain. The urine may be cloudy or discolored.
A bladder infection must be treated early to prevent complications. A particularly dangerous complication is pyelonephritis, which can cause severe symptoms and become chronic.
Urinary stones
Under certain circumstances, crystals can form from the components of urine, which combine to form urinary stones. These can grow up to several centimetres in size and are found in the kidneys, ureter, bladder or urethra. Those affected often do not even notice smaller stones and simply excrete them with their urine.
Larger stones can cause severe pain (colic), cause inflammation or block or injure the urinary tract if they start to move. In such cases, the urinary stones are usually removed as part of a minor operation.
Urinary incontinence - a problem for women in particular
The sphincter muscles in the bladder and urethra are significantly weaker in women than in men. Furthermore, pregnancy, childbirth and hormonal changes during the menopause can put a lot of strain on the pelvic floor. This can result in urinary incontinence, which means that urine is passed involuntarily.
The symptoms can often be improved with special strengthening exercises for the pelvic floor.
Urinary retention - a dangerous emergency
If it is not possible to empty the bladder, this is known as urinary retention or urinary retention.
There are many reasons for this: the urinary tract can be obstructed by a trapped urinary stone, a foreign body in the urethra, an enlarged prostate, injuries or tumors. Congenital malformations of the urinary tract also sometimes lead to urinary retention. Certain medications or surgical procedures can promote urinary retention. Some neurological and psychological problems also prevent the bladder from emptying spontaneously.
Urinary retention can cause severe pain or be almost symptom-free. If the bladder remains excessively full for a long period of time, the sphincter muscle will eventually give way, resulting in an overflow bladder with involuntary urination. The sphincter muscle can be permanently damaged, resulting in urinary incontinence. It can also result in kidney damage.
Urinary retention therefore requires rapid treatment . A catheter is then used to drain the urine and relieve the bladder.
Other diseases of the urinary tract
In addition to those already mentioned, other diseases of the urinary tract also occur:
- Especially in male newborns, malformations of the urinary tract are observed from time to time, for example a wrong course or the formation of two urethras.
- Tumors can develop in the bladder or urethra, as in most other organs.
