Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Zollinger-Ellison Syndrome ?
    ### Response:
    The stomach, duodenum, and pancreas are digestive organs that break down food and liquid.
                
- The stomach stores swallowed food and liquid. The muscle action of the lower part of the stomach mixes the food and liquid with digestive juice. Partially digested food and liquid slowly move into the duodenum and are further broken down.
    