The digestive system is responsible for breaking down food into small pieces so that various substances can be absorbed into and transported around the body. This process is both physical and chemical.
The physical processes consist of chewing the food in the mouth, using teeth to cut up and grind down the food into smaller pieces before it is swallowed. Muscles in the gullet aid the process of swallowing and, as they contract, they push the food towards the stomach. Here, the physical process continues as muscles in the stomach wall contract and churn the food.
The chemical process breaks down the food further (through chemical reactions) so that it becomes soluble and small enough to be absorbed into body. This chemical process uses different enzymes that speed up these chemical reactions.