Mechanical Digestion of Food

Mechanical digestion refers to the physical breakdown of food into smaller pieces without changing its chemical composition.

Process of Mechanical Digestion

Mechanical digestion begins in the mouth where teeth cut, tear, and grind food. The tongue mixes food with saliva and forms a bolus. Peristalsis in the oesophagus pushes food toward the stomach. In the stomach, muscular contractions churn food and mix it with gastric juices, producing chyme. These actions increase the surface area available for enzyme activity.

---

Role of the Oral Cavity and Pharynx

Oral Cavity (Mouth)

The mouth is the first organ of the digestive system. Teeth perform mastication, while saliva moistens food and begins starch digestion through salivary amylase. The tongue helps in chewing, tasting, and swallowing.

Pharynx

The pharynx acts as a passageway for food and air. During swallowing, the epiglottis closes the airway and directs food into the oesophagus, preventing choking.