Bladder

The bladder is part of the urinary system.

Function of the bladder

The bladder receives urine from the kidneys via the ureter. Its purpose is to store it before it is removed during micturition through the urethra. The muscles surrounding the bladder avoid reflux of urine into the ureter.

Structure of the bladder

The bladder is a hollow organ surrounded by three layers of smooth muscles, all of which as a group is called the detrusor:

• the plexiform layer;
• the circular layer;
• the longitudinal layer.

Internally, the bladder is covered by the urotheliuma, which is a layer of epithelium.

The bladder can contain between 400 and 700 millilitres of urine and varies in size proportionate to general morphology. People feel the need to urinate when the bladder s 300 millilitres or more.

During micturition which is a reflex act, the muscles contract and the smooth muscle sphincter relaxes. This reflex can be inhibited in human beings from learning body hygiene.