Physical digestion

Physical digestion increases the surface area of food particles. This larger surface area allows digestive enzymes to act more effectively during chemical digestion.

The four types of human teeth are incisors, canines, premolars, and molars. Each type is adapted for a specific function in physical digestion.

A human tooth consists of enamel, dentine, pulp (containing nerves and blood vessels), cement, and is embedded in the jaw bone and gums. Enamel is the hardest outermost layer protecting the tooth.

Incisors are chisel-shaped teeth located at the front of the mouth. Their primary function is for biting and cutting food into smaller pieces.

Canines are cone-shaped teeth located next to the incisors. Their main function is tearing and gripping food.

Premolars and molars are located at the back of the mouth and have broad, flat surfaces. They are used for grinding and crushing food into smaller particles, increasing the surface area for enzyme action.

The stomach's muscular walls contract and relax to churn food, mixing it with gastric juices and breaking it down physically. This churning action helps to increase the surface area of the food.

Bile emulsifies fats and oils into smaller droplets. This increases the surface area of the fats, allowing for more efficient digestion by lipase, an enzyme that breaks down fats.