The mouth – the entrance to the gastrointestinal tract

Bounded by the lips, the cheeks, the palate and the tongue, the mouth is responsible for the first stage of digestion: the ingestion of food. It also enables the body to start breaking down this food by means of chewing with the aid of our teeth (20 in children and 32 in adults), mixing and then swallowing it. The tongue plays an important role in this process, not only through the movements that enable food to be replaced continuously between the teeth, but also through the mixture of food with saliva to form the food bolus. Saliva is also responsible for part of the digestive process: the release of the sugars in food thanks to the enzyme it contains (amylase).

 

Made up of almost 98% water, saliva is produced continuously and its secretion is increased even before the food enters our mouth, when we see or smell food for example, or even just think about it. We produce approximately 1 to 1.5 litres of saliva every day, a quantity that would fill an entire swimming pool over the course of a lifetime (4 x 8 m in area and 1.5 m deep).

Texture, also a cultural issue

The Inuits and the Argentinians like to eat tough foods that require a strong chewing action, while the Mexicans and a number of African nations enjoy a softer consistency. In Europe, every region has its own type of bread. Northern eaters prefer their bread soft, while the Southerners enjoy a crispy crust, which explains the success of the French baguette.