The mouth and the stomach are both sites of mechanical and chemical digestion of food.
Digestion in the Mouth:
In the mouth, the teeth grind and mash the food into smaller pieces that aid in proper digestion.
Saliva produced in the mouth contains the carbohydrate digesting enzyme, salivary amylase.
Digestion in the Stomach:
In the stomach, protein is mainly digested by the combined action of low pH, protease enzymes like pepsin and the contraction of the muscles of the stomach.
Pepsin breaks down protein in the presence of stomach acids.
The muscles of the stomach contract and relax and aid in mixing the enzymes and acid together, consequently, aiding in digestion.
