The mouth (by chewing) and the stomach (by gastric motion).
oral cavity and stomach
The mouth and the stomach are two anatomical regions involved in the mechanical breakdown of food. In the mouth, teeth mechanically break down food into smaller pieces through mastication. In the stomach, muscular contractions churn and mix food with digestive juices to further break it down into a semi-liquid state.
They are the teeth. Stomach also involve in mechanical digestion
Peristalsis. The movement of muscles bringing the food to the stomach.
Chruning
The mouth, specifically the teeth, breaks down food mechanically through the process of chewing. The stomach also contributes to mechanical breakdown through muscle contractions that help mix and churn food.
initiates protein digestion and denatures proteins
The third layer of smooth muscle found in the stomach wall is called the oblique layer. It runs diagonally and allows for churning and mixing of food, aiding in mechanical breakdown and digestion.
mechanical breakdown
The stomach has a very acidic environment. This favors the breakdown of proteins. An enzyme (i.e. a biological catalyst) called trypsin is active at acidic conditions (gastric juice) and is responsible for the break down of proteins in the stomach.
Mechanical breakdown makes food smaller so it wasn't be so large for the chemical breakdown.