Teeth & Digestion (Cambridge International IGCSE Biology)

Types of Human Teeth

Spec point — Identify in diagrams and images the types of human teeth: incisors, canines, premolars and molars Describe the functions of the types of human teeth in physical digestion of food

• Mechanical digestion is the breakdown of food into smaller pieces without chemical change to the food molecules

• It is carried out by the:

  • chewing action of teeth
  • churning action of the stomach
  • emulsification of fats by bile in the duodenum

• Teeth are located in the bone of the jaws

• They are used for chewing to increase the surface area of the food

  • This increases the food's exposure to saliva and digestive enzymes so that it can be broken down more quickly

• Different teeth have different shapes, enabling them to perform slightly different functions:

  • incisors are chisel-shaped for biting and cutting
  • canines are pointed for tearing, holding and biting
  • premolars and molars are large, flat surfaces with ridges for chewing and grinding up food

Teeth are shaped to carry out different roles in mechanical digestion of food

Structure of a Tooth

Spec point — 7.3.4 · Describe the structure of human teeth, limited to: enamel, dentine, pulp, nerves, blood vessels and cement, and understand that teeth are embedded in bone and the gums

• Teeth are embedded in the gums and within the bone of the jaw

• The structure of human teeth includes:

  • enamel: the hard, outer layer that protects the teeth
  • dentine: the layer beneath the enamel that protects the nerves
  • pulp: the soft, internal tissue of the tooth that contains nerves and blood vessels
  • cement: a hard layer around the root of a tooth that helps to anchor it within the jaw

Teeth are embedded in the gums and within the bone of the jaw