The Mouth and the Teeth
Where does digestion begin? What helps make digestion possible? How does digestion happen?
Digestion begins in the mouth where the food is chewed and cut into small pieces. The teeth breakdown, chop, and grind the food so that it can be swallowed easily. Different teeth perform different functions in breaking down food.
The incisors cut the food. The cuspids tear it. The molars grind and crush the food. How do they do this? Look at the different shapes of the teeth. How are their shapes related to their functions?
PERMANENT TEETH
1. Central Incisors 2. Lateral Incisors
3. Canines
4. First Bicuspids
5. Second Bicuspids
6. First Molar
7. Second Molars
8. Third Molars
The saliva mixes with and wets the food. Saliva is a digestive juice which is secreted by the three pairs of salivary glands that empty into the mouth. It contains an enzyme ptyalin wich acts on starches and changes them into sugar.
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