The amounts of fluid we drink every day must be excreted again through the urinary tract. The discharge from the body takes place through the emptying of the bladder – micturition.
What is micturition?
In medical jargon, the term micturition stands for the emptying of the urinary bladder. The term micturition in medical jargon stands for the emptying of the urinary bladder. The control of the emptying of the bladder is a complex interaction. In the urinary bladder, receptors in the bladder wall respond to the degree of filling of the bladder. When the pressure rises, they signal an urge to urinate and we get the feeling that we need to visit a toilet. Older children and adults can usually consciously control this process, delaying going to the toilet or giving in to the urge to urinate and emptying the bladder. After a certain point of bladder filling, however, urination can no longer be controlled and functions reflexively. How intense bladder pressure is experienced is individual. Bladder emptying can be trained through targeted bladder training. This training is used for therapy in the case of incontinence problems, but can also be used if a person has the feeling that they have to go to the toilet very frequently without having drunk much. In most cases, this feeling arises from the habit of going to the toilet very frequently. Consciously holding out for longer periods of time can now delay the urge to bladder.
Function and task
The fluid we consume each day must be adequately processed by the body and expelled from the body again. This is done through the urinary tract. The fluid is converted to urine in the kidneys, and from there it is passed through the ureter into the urinary bladder. The urinary bladder is a hollow organ and serves as a storage organ for urine. Up to a maximum of 800 ml of urine can be collected there. An urge to urinate already occurs at about 200 to 400 ml of urine. From about 800 ml of urine in the bladder, however, voluntary control is no longer possible. From time to time, the bladder must be emptied and the urine must be transported out of the body. During the phase in which the bladder slowly fills, the bladder muscles remain inactive and expand to accommodate the urine. During this process, the bladder remains closed by the sphincter muscle. As it fills more and more, urination occurs. The emptying can be controlled by the will. When the bladder is emptied, the bladder muscles contract, the sphincter muscle becomes slack and the bladder can be emptied. When the urge to urinate becomes stronger, people visit a toilet to empty the bladder. How often it needs to be emptied varies from person to person. Depending on the amount of fluid we take in, we urinate up to 8 times a day. Urination takes place in 4 phases. At the beginning, the bladder muscles contract. The contraction opens the internal sphincter in front of the urethra, then the external sphincter. Finally, the urine flows out through the urethra. This process is assisted by the abdominal and pelvic floor muscles. The process of micturition is controlled by the brain. The bladder muscles react to the filling quantity in the bladder and report impulses to the brain via the nerve pathways. When there is approximately 350 ml of urine in the bladder, the cerebrum registers the urge to urinate and controls the bladder emptying reflex via the spinal cord when urination occurs by sending impulses to contract the bladder muscles and relax the internal and external sphincters. The reflex to empty the bladder can be suppressed and controlled to a certain extent, with the brain sending inhibitory impulses to the bladder muscles via the spinal cord. In some people, especially the elderly or those with incontinence problems, voluntary control may be impaired and must be retrained through therapeutic measures.
Diseases and conditions
If the interaction of bladder emptying does not function optimally, disorders and associated discomfort may occur. During normal urination, the bladder is completely emptied several times a day. If emptying the bladder is difficult (dysuria) due to a narrowed or blocked urethra, e.g. in the case of an enlarged prostate, bladder stones or tumors, urination may be associated with pain. In the case of infections, pregnancy, tumors and a permanent catheter, frequent emptying of the bladder may occur, but only a little urine is passed (pollakiuria).In polyuria, an excessive amount of urine is excreted during the day. The reasons are usually diabetes mellitus or the use of diuretic medications. In nocturia, sufferers have to empty their bladder at night despite taking in normal amounts of fluid. The cause may be cardiac insufficiency or a bladder infection. Sometimes, however, it is simply a psychological assumption that suggests a high urge to urinate. Urinary retention (anuria) can be caused by mechanical obstructions in the urinary tract such as stones, tumors, foreign bodies or prostate enlargement, but also by psychological influences such as a blockage to urinate in the presence of other people (paruresis). In the case of urinary retention, there is a risk of residual urine formation, which can cause a bladder infection, usually associated with pain and burning during urination. In irritable bladder, there is a frequent urge to urinate, often associated with a fear of not being able to reach a toilet in time. Irritable bladder is also sensitive to cold. In the case of bladder weakness (incontinence), there is an unintentional leakage of urine, which is associated with shame for those affected. There are various forms of incontinence in which the closure mechanism of the bladder does not function optimally or the physical interaction of micturition is disturbed by various influences. They include stress incontinence, urge incontinence, overflow incontinence, reflex incontinence and extraurethral urinary incontinence.
