Could you tell me what happens when the pancreas shuts down?

Depends on sxs: Most organs in the body are quite resilient until late stages of a disease. The pancreas has two main functions: 1) to produce Insulin and 2) to make and transport enzymes into the gut that help digest food. When the pancreas "shuts down" or becomes insufficient it more likely refers to enzyme deficiencies and digestive problems that can be helped with supplements. Diabetes is different.