DIGESTIVE SYSTEM
The food we eat enters the body through the mouth.
The food is chewed by the teeth and begins its gradual transformation under the action of enzymes, such as amylase, contained in digestive juices, released by the salivary glands.
Saliva moistens the food and the enzymes initiate the chemical digestion of carbohydrates.
The processed food, in boluses, is transported to the esophagus by the movements of the tongue and then, through the contraction of the esophagus, reaches the stomach, where the food will remain for one to four hours.
The food is mixed and continues its transformation into a paste.
The enzymes in the digestive juices partially break down the molecules of different food categories.
It is in the small intestine, a digestive tube that varies in size between 4 and 7 meters in length, that glucose, fatty acids, and amino acids are directly assimilated by the body.
It is in the small intestine that they will pass into the bloodstream. This absorption occurs at the level of the intestinal villi - those microscopic folds in the intestinal wall, numbering almost 10 million, allowing the intestine to offer an absorption surface of about 250 square meters.
Undigested food passes into the large intestine and is pushed out of the body at the anus.
It is the nutrients from food digestion that will provide energy to the body's cells and allow the organs to function properly. They are therefore a source of energy, released during chemical reactions and converted by the body into mechanical and thermal energy.