The bladder is a hollow, balloon-like organ in the lower abdomen that stores and collects urine. Urine is composed of water and waste products filtered out of the blood by the kidneys and passed into the bladder through two tubes called ureters. Urine leaves the bladder through a tube called the urethra.

Two tight bands of muscle (sphincters) control urine flow into and out of the bladder. Like a balloon, the bladder's elastic walls stretch to store urine. When urine is emptied out, the walls flatten together.

A layer of muscle surrounds the inner lining of the bladder. When the bladder becomes full, nerve signals are sent to the brain, which instructs the sphincter at the base of the bladder to relax and the muscles in the bladder wall to squeeze the bladder and push the urine out. These instructions from the brain can normally be controlled voluntarily, so that the person can choose when to urinate.


Bladder conditions

Urinary Tract Infections (UTI)

Urinary tract infections (UTIs) are the second most common kind of infection (after chest infections). The urinary tract is made up of the kidneys, ureters (the tubes from the kidneys to the bladder), the bladder and the urethra (the tube which expels urine from the bladder).

Read more

Bladder cancer

Bladder cancer mostly affects people who are over 50 and is twice as likely to occur in men as in women. In the UK, over 10,000 new cases of bladder cancer are diagnosed each year, making it the fourth most common cancer in men and the 12th most common in women.

Read more

Urinary Incontinence

The bladder usually stores urine until you choose to empty it. Urinary incontinence occurs when you pass water involuntarily. It can happen to people at any age. In the United Kingdom, at least 3 million adults cannot control their bladders as they would wish.

Read more

Interstitial Cystitis

Interstitial cystitis is caused by inflammation of the bladder lining. It is also known as painful bladder syndrome, chronic pelvic pain syndrome and frequency-urgency-dysuria syndrome.

Read more


Read more


Read more

Male reproductive organs

Read more

You might also like…

Your stories

Sometime's it's the people you least expect

Read Paul’s story Read all stories