The gall bladder is a small pear-shaped organ found behind and just beneath the liver. It's about 3 inches long and is connected to the liver by bile ducts. The bladder holds gall, which is a greenish fluid that helps to digest fatty foods. To do this, the bladder secretes gall into the upper part of the small intestine after it has received hormonal signals.
The urinary bladder is found in the pelvic area and is connected to the kidneys by ureters. When empty, the urinary bladder is flat, but as the kidneys release urine, the bladder expands to accommodate the increasing volume of fluid. A urinary bladder can hold between 400 and 600 milliliters of urine.
As the amount of urine increases, an individual begins to feel the urge to urinate. After toddlerhood, urination in humans is largely voluntary. During urination, the muscles of the bladder contract and two valves open, letting the urine exit via the urethra. One of those muscles is controlled voluntarily, while the action of the other is involuntary.Learn more about Human Anatomy