• Mechanical digestion is the?breakdown of food into smaller pieces?without chemical change to the food molecules
• It is mainly carried out by the?chewing?action of the?teeth, the?churning?action of the?stomach?and the?emulsification of fats?by?bile?in the duodenum
• Teeth are held firmly in the bone of the jaw
  • They are used for chewing?to increase the surface area of the food?so that it can be exposed to?saliva?and other digestive juices and?broken down?more quickly
• The differing shapes and sizes of teeth enable them to perform slightly different functions:
  • Incisors?- chisel-shaped for biting and cutting
  • Canines?- pointed for tearing, holding and biting
  • Premolars and molars?- larger, flat surfaces with ridges at the edges for chewing and grinding up food

Types of teeth

Structure of a typical tooth

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