What is digestion?

The idea

Digestion is the process of breaking complex food components into simpler forms in the body; food is partially digested in the mouth.

A new word

In the mouth, saliva changed some starch into sugar. Scientists have a name for this kind of change.

What do you think digestion means?

• Breaking complex food into simpler forms in the body
• Eating food very fast
• Washing food with water

Break it down

Press In the mouth. Then press Whole canal. Watch the three chains of food.

Partly in the mouth

In the mouth only some of the starch was changed. The rest of the digestion carries on along the canal.

Digestion is the process of breaking complex food components into simpler forms in the body. Food is partially digested in the mouth.

Notes

Digestion is the process of breaking complex food components into simpler forms in the body. Food is partially digested in the mouth.

Check yourself

Digestion means …

How much of our food is digested in the mouth?

Where does the rest of the digestion happen?

What does saliva begin to digest in the mouth?

• making food bigger. Digestion makes food simpler, not bigger.
• breaking complex food into simpler forms — correct. Yes!
• only swallowing food. Swallowing moves food down. Digestion breaks it into simpler forms.
• All of it. Only some of it, such as part of the starch, is changed in the mouth. The digestion carries on later.
• None of it. Saliva starts to break down starch in the mouth, so food is partly digested there.
• Only partly — correct. Yes!
• Further along the alimentary canal — correct. Yes!
• Only in the nose. The nose is for smelling and breathing, not for digesting food.
• Outside the body. Digestion happens inside the body, along the alimentary canal.
• Fat. In the mouth, saliva acts on starch. Fat is dealt with later, with the help of bile.
• Starch — correct. Yes!
• Water. Water is already simple. It does not need digesting.