The urinary bladder (often simply called the bladder) is located in the lower part of the abdominal cavity. It rests on the pelvic floor and is well protected by the pelvis. In women, it sits directly in front of the uterus; in men, it is adjacent to the rectum.
At the back, the bladder is connected to the kidneys via the two ureters. The kidneys constantly release urine, thereby filling the bladder. At the bottom, the bladder opens into the urethra, through which it can be emptied.
The bladder is highly elastic and expands as it fills. The amount of urine the bladder can hold varies. Men’s bladders tend to be larger, but capacity also depends on body size and other factors.
Stretch receptors in the bladder wall signal the level of fullness to the brain. When the bladder is about half full, you therefore feel the urge to empty it. This urge becomes stronger as the bladder continues to fill.
Thanks to the sphincter muscles, you can, to a certain extent, consciously decide when to empty your bladder. These muscles consist of various muscle bundles. One muscle band, made up of “smooth” muscle, runs in a ring around the bladder neck. A second muscle band, made up of “striated” muscle, is located
- in women in the lower third of the urethra,
- in men, it extends along its entire length.
This second layer of muscle can be consciously relaxed, thereby allowing the bladder to empty.
The bladder muscles are supported by the pelvic floor muscles. They hold the urethra and the bladder neck in place. Without the bladder and its sphincter muscles, one would constantly leak urine instead of being able to control urination.
The anatomy of the bladder in men © bilderzwerg #75130881 | AdobeStock
A bladder infection (cystitis) is an infection of the bladder caused by bacteria. The pathogens enter the bladder through the urethra.
Typical symptoms include a frequent urge to urinate and a burning sensation or pain when urinating. The urine may be cloudy or contain blood. An untreated bladder infection can lead to a kidney infection or pyelonephritis.
Prompt treatment is especially important for pregnant women to prevent complications such as premature labor.
Mild bladder infections can often be effectively treated with home remedies and increased fluid intake. In many cases, however, antibiotics are necessary. Since the urethra is significantly shorter in women than in men, bladder infections are more common in women.
Urinary incontinence, or bladder weakness, refers to the involuntary loss of urine
- when coughing,
- laughing,
- during physical exertion, or
even without any apparent trigger. Just like bladder infections, bladder weakness is more common in women than in men.
The causes can vary widely. Possible causes include, for example:
- a weakened pelvic floor, for example due to pregnancies and childbirth or hormonal changes during menopause
- injuries or surgeries in the pelvic area
- nerve damage or irritation
- neurological disorders such as multiple sclerosis or Parkinson’s disease
- Bladder stones or recurrent bladder infections
- Excessive strain on the pelvic floor due to chronic coughing or chronic constipation
- Risk factors such as obesity, strenuous physical activity, and lack of exercise
- Medications that increase the risk of incontinence
As with most other organs, cancer can develop on or in the bladder. Men are affected significantly more often than women.
Risk factors include
- smoking,
- regular exposure to certain dyes, and
- excessive use of certain pain medications.
In most cases, these are so-called “cauliflower tumors” or papillomas. They tend to grow superficially on the layer of cells lining the inside of the bladder. This type can often be treated effectively during a cystoscopy. However, tumors that affect deeper layers also occur.
Possible symptoms of bladder cancer include:
- Blood in the urine
- Pain in the flank area
- A strong urge to urinate
- Incomplete emptying of the bladder
- Burning sensation when urinating
Symptoms such as these should therefore always be evaluated by a doctor.
In addition to the bladder conditions mentioned above, there are others, such as:
Bladder stones or bladder grit are relatively rare in humans. However, they can cause severe lower abdominal pain and damage the bladder wall or urethra. If they are too large to pass on their own, they are usually碎ed during a cystoscopy and then removed.
In bladder prolapse, the bladder shifts backward and downward. Due to the bladder’s anatomical location, this condition occurs almost exclusively in women. It can be a cause of incontinence.
Urination disorders refer to general difficulties with urination. These include, for example,
- incomplete emptying,
- frequent urge to urinate, or
- excessive nighttime urge to urinate.
An increased or decreased urine output may also occur. The causes and treatment options for voiding disorders are varied. In a bladder rupture, the bladder lining tears, allowing urine to leak into the abdominal cavity. A rupture causes severe pain and can lead to peritonitis, which, in the worst case, is life-threatening.
The bladder is a complex organ whose function is closely linked to the storage and transport of urine. It is located in the pelvis, with the ureters emptying into the bladder and urine being excreted through the urethra. The bladder fills gradually until increasing volume triggers the urge to urinate.
The detrusor muscle, a smooth muscle, works together with the sphincters to ensure controlled urination. The bladder is innervated by a complex plexus system that enables voluntary control. The urothelium and the bladder base also play an important role in its function. The bladder serves to store urine and adapts flexibly due to its maximum capacity. Anatomically, the bladder is located cranially in the pelvis and is partially covered by the peritoneum. The topography of the bladder shows close relationships with the abdominal cavity and surrounding connective tissue.
There are many bladder disorders, including cystitis, urinary incontinence, and stress incontinence. Blood in the urine can also be a sign of a disorder. In severe cases, removal of the bladder may be necessary. Overall, the bladder is a central component of the urinary tract, and its structure and function are crucial for the entire body.
What is the function of the bladder?
The function of the bladder is to store urine and allow for controlled urination. It enables the excretion of urine through the urethra.
How does the bladder work?
The bladder continuously fills with urine. Once it is sufficiently full, urination is triggered by micturition, which is controlled by the innervation of the bladder and the sphincter muscles.
Where is the bladder located in the body?
The bladder is located in the pelvis. It lies below the abdominal cavity and changes position depending on how full it is.
What are some bladder disorders?
The most common bladder conditions include cystitis, overactive bladder, and urinary incontinence. Tumors or blood in the urine may also occur.
What is the capacity of the bladder?
Its maximum capacity is several hundred milliliters. A full bladder can expand significantly before it needs to be emptied.
