Page 14 - exemple

2 The stomach

Food is conducted to the stomach through the
esophagus. Esophagus

The esophagus is a muscular tube that allows the
conduction of food to the stomach by a special
movement called the peristaltic movement (Doc. 4). Stomach

The muscular wall of the stomach allows, by its
contraction, the grinding and the mixing of food with Small intestine
the gastric juice.
Doc 3- The digestive tract.
The activity of the stomach is facilitated when the food is well
chewed.

The glands of the wall of the stomach secrete the gastric juice.
The chyme exiting the stomach passes to the small intestine

The food takes eight seconds to pass from the mouth to the
stomach where it stays for about four hours before continuing its
route towards the small intestine. Doc 4- Peristaltic movement

of the esophagus.
3 In the small intestine

Although the mixing of the food occurs in the small
intestine, the mechanical digestion is slow. At the level

of the small intestine, digestion is mainly chemical
since at this level, the proteins, the carbohydrates and
Doc 5- Contraction
the lipids are digested by the enzymes found in the of the gastric wall
pancreatic juice and the intestinal juice. in red and the
progress of food in
green.

Probing of activity 1

1- List the different parts of the digestive system.
2- What does a mechanical transformation consist of?
3- Locate the organ(s) in which the food is mixed.
4- For which reason can we eat when the head is upside?

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