The organ in the digestive system that has a function most similar to the function of a bladder in the excretory system is the gallbladder. The gallbladder stores and concentrates bile produced by the liver until it is needed for digestion. Similarly, the bladder in the excretory system stores and holds urine until it is ready to be expelled from the body.
The organ in the digestive system that has a function most similar to the function of a bladder in the excretory system is the stomach. While the bladder stores and releases urine in the excretory system, the stomach stores food and releases it in a controlled manner into the small intestine during digestion. Both the bladder and the stomach have the ability to expand and contract to accommodate and release their respective substances.
