bladder

Dr. Manuela Mai studied medicine at the Universities of Heidelberg and Mannheim. After graduating, she gained clinical experience in gynecology, pathology and clinical pharmacology. She is particularly interested in the broader connections that lead to diseases - also outside of conventional medicine. She completed additional training in classical homeopathy as well as ear and skull acupuncture.

More about the experts All content is checked by medical journalists.

The urinary bladder (Vesica urinaria) is a stretchy, muscular hollow organ. It collects and stores the urine from the ureters until it is emptied via the urethra. You feel the urge to urinate when the bladder is filled to a certain extent. The function and location of your sphincter muscles are responsible for ensuring that the continuously produced urine can be emptied in a controlled manner. Read more about the function of the urinary bladder and the problems it can cause here.

What is the urinary bladder?

The urinary bladder, colloquially known as the “bladder” for short, is an expandable hollow organ in which urine is temporarily stored. It is deliberately emptied from time to time (micturition). The human bladder has a maximum capacity of 900 to 1,500 milliliters. Due to its elasticity, it changes its shape from spherical to finally pear-shaped with increasing filling.

Anatomy: bladder

The human bladder is divided into three sections. A distinction is made between the apex of the bladder, the body of the bladder (corpus) in the middle and the base of the bladder (fundus) below. The skin of the bladder is wrinkled so that it can enlarge if necessary. When filled, the apex of the bladder can be felt through the abdominal wall.

The two ureters open into the upper part of the urinary bladder. Due to its inclined course and its slit-shaped mouth, a valve-like closure is created, so that a back flow of urine towards the kidneys is prevented.

The urine is stored in the bladder. This tapers like a funnel downwards in the direction of the urethra (urethra), this part of the urinary bladder is also called the bladder neck. The neck and base of the bladder rest on the pelvic floor. The urethra runs through the pelvic floor. They drain the urine.

In the area of ​​the urethral orifice there are two sphincters that prevent urine from leaking out of the urinary bladder. If the bladder is emptied voluntarily or involuntarily - for example with incontinence, the smooth muscles of the bladder wall contract, the sphincter muscles open and the urine can flow out through the urethra. These processes are controlled by nerve impulses from the sacral nerve plexus (sacral plexus).

The urinary bladder is lined with a mucous membrane for protection. The outer layer of the bladder consists of smooth muscles that involuntarily contract when it is emptied. The contents of the bladder are pressed out of the bladder, supported by the arbitrarily controllable abdominal and pelvic muscles.

What is the function of the bladder?

The urinary bladder serves as a temporary store for the urine. This is where the waste product is collected and stored to be disposed of when the opportunity arises. Since the kidneys are continuously producing urine, without a bladder, urine would be excreted all the time.

The mouth of the urethra is tightly closed by two sphincters. Only the external sphincter can be opened and closed at will. The internal sphincter opens reflexively. This normally ensures that the bladder can be emptied at will from time to time. In the time between evacuations, the bladder is tightly closed - unless the volume of fluid exceeds its capacity.

“Bladder full” - this signal reaches the brain much earlier, thanks to sensors in the bladder wall, which are stretched as the bladder content increases. In adults, the urge to urinate usually occurs from a filling quantity of 200 to 500 milliliters. From this bladder content onwards, one feels the urgent need to empty the urinary bladder.

Men and women each have different bladder volumes. In women it is smaller because the uterus also takes up space in the abdomen. In addition, each person also has an individually different capacity. And: How quickly you feel that you have to pursue the urge can be trained. Finally, during emptying, an interplay of voluntary and reflex muscle activity ensures that the urine can drain.

Where is the urinary bladder located?

The urinary bladder is located in the small pelvis, behind the pubic bones and the pubic symphysis. When empty, the bowl-shaped bladder does not exceed the upper edge of the pubic bones and can therefore not be felt through the abdominal wall. One wonders: where exactly is the bladder? On the other hand, the situation can easily be determined with increasing urine filling. Here, the pressure with the hand on the bladder increases the urge to urinate and thus allows the localization to be very good.

If the urinary bladder fills up, it expands towards the navel, but does not reach it even when it is fully filled.

In women, the urinary bladder adjoins the uterus (uterus) in the rear area of ​​the pelvis, in men the rectum adjoins the back. In both sexes, the bladder lies on the pelvic floor and the urethra runs through the pelvic floor. The two sphincter muscles of the urinary bladder are also found in this area.
The upper and rear areas of the urinary bladder are covered by the peritoneum, so it lies outside the abdominal cavity.

What problems can the bladder cause?

There are a variety of acquired and congenital bladder disorders. Men and women are equally affected. However, women are more likely to suffer from inflammation of the urinary bladder (cystitis). Because with them, the shorter urethra makes it easier for germs to rise into the bladder and infect it.

Women are also more prone to bladder weakness (incontinence), of which there are different forms. In most cases, bladder weakness is related to a weakening of the pelvic floor, which is weakened by childbirth, for example. But there are also other triggers: consequences of an injury, urinary bladder or uterine prolapse or neurological diseases. If men suffer from incontinence, surgery, such as removal of the prostate, is often the cause. Pelvic floor exercises can often help.

In addition, there is also the so-called irritable bladder. This manifests itself in a constant, often attack-like urge to urinate, although only small amounts of urine are ever released from the urinary bladder. The explanation can sometimes be found in neurological diseases, bladder stones, bladder tumors or infections. Very often the cause remains unexplained.

Bladder stones can be very painful and uncomfortable. Here, substances crystallize out of the urine and form solid components. Above all, these lead to discomfort if they obstruct the urethra or pass through it.

Tumors can also form on the urinary bladder (bladder cancer), this mainly happens in old age. Other possible diseases are urinary bladder fistulas or sac-like protuberances on the bladder wall (urinary bladder diverticulum)

If the filled bladder cannot be emptied naturally, this is called urinary retention. This condition is a medical emergency and can cause kidney damage.

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