Mastication

Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding.

The muscles of mastication move the jaws to bring the teeth into intermittent contact, repeatedly occluding and opening. As chewing continues, the food is made softer and warmer, and the enzymes in saliva begin to break down carbohydrates in the food. After chewing, the food (now called a bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs.

Muscles involved in Mastication

The muscles that are responsible for the primary movements of the jaw are the masseter, the temporalis, the medial pterygoid, and the lateral pterygoid. These muscles are responsible for the forceful closing of the jaw, and also play a role in the side-to-side grinding of the teeth.

Process of Mastication

The process of mastication has two phases: the opening phase and the closing phase. During the opening phase, the mandible is lowered by the relaxation of the temporalis and masseter and contraction of the lateral pterygoids. During the closing phase, the masseter and the temporalis contract and the mandible is raised.

Role in Digestion

Mastication plays a vital role in the digestive system. It not only physically breaks down food into smaller pieces to increase surface area for digestion, but also mixes food with saliva. Saliva contains digestive enzymes that begin the process of digestion by breaking down starch and fat in food.

See also

• Digestion
• Human tooth
• Saliva
• Enzyme

Mastication Resources
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