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Activity 1 The mechanical digestion

In the digestive system, liquid foods are directly swallowed; solid foods are chewed or masticated

by the teeth (mechanical digestion). What are the organs involved in the mechanical digestion?

1 The mouth

Humans have two dentitions throughout their life: the
milk teeth and the definitive teeth including 32 teeth.
Foodstuffs go through a mechanical digestion by the
teeth: the teeth are structures that cut, tear and grind the

food. Grinded food is then impregnated with saliva
which facilitates its swallowing. Doc 1- Adult human dentition showing 4
The mechanical digestion is accompanied by a different types of teeth.
chemical one that will be developed later in the chapter.

The tongue mixes food with saliva.

Digestion occurs all along the digestive tract even if each part possesses a specific role.
An involuntary mechanism prevents food from passing into the respiratory tracts and guides it

through the pharynx to the esophagus.
Three pairs of salivary glands are found in the mouth and secrete a digestive juice: saliva.

Food
Nasal cavities
Lip
Veil of
Teeth the palate

Tongue Epiglottis
Pharynx

Trachea Esophagus

Doc 2- The passage of the grinded food into the esophagus.

Digestion 17