What is a sac like muscular organ?

A sac-like muscular organ refers to structures in the body that are composed of muscle tissue and can expand or contract to store or move substances. One example is the stomach, which is a muscular organ that helps in digesting food by churning it and mixing it with digestive juices. Another example is the bladder, which stores urine before it is excreted from the body. These organs play crucial roles in various bodily functions, including digestion and waste elimination.