The urinary bladder is a musculo-membranous sac which acts as a reservoir for the urine; and as its size, position, and relations vary according to the amount of fluid it contains. It receives urine from the kidneys through the ureters and is dispensed from the bladder through the Urethra.
When the bladder is moderately full it contains about 0.5 litres and assumes an oval form; the long diameter of the oval measures about 12 cm. and is directed upward and forward. The bladder capacity decreases with old age.
Nerves in the bladder tell you when it is time to urinate (empty your bladder). As the bladder first fills with
urine, you may notice a feeling that you need to urinate. The sensation to urinate becomes stronger as the bladder continues to fill and reaches its limit. At that point, nerves from the bladder send a message to the brain that the bladder is full, and your urge to empty your bladder intensifies.
Click on the below topics to know about urinary problems and treatments.