LE SYSTEM LE SYSTEM DIGESTIFDIGESTIF

Biologie F 11Biologie F 11CHSCHS

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SYSTEM DIGESTIFSYSTEM DIGESTIF

Le Processus Le Processus DigestifDigestif

Le processus commence dans la Le processus commence dans la bouchebouche::

La nourriture est partiellement La nourriture est partiellement briser par le processus de mâcher briser par le processus de mâcher (mastication). (mastication).

Les glands salivaires produit la Les glands salivaires produit la salive et brises l’amidon (starche) salive et brises l’amidon (starche) chimiquement.chimiquement.

Le chemin a l’estomac

L’ œsophage – Après que la nourriture est mâcher et avaler, ca descend l’œsophage. L’œsophage est un longue tube qui conduit de la bouche a l’estomac.Les muscles de l’œsophage contracte rythmiquement (appeler peristalse) pour pousser la nourriture de la gorge a l’estomac.

Dans l’estomac•L’estomac est un grand organe dans la forme d’un sac.• La nourriture est tourbillonner (churned) dans l’estomac et l’acide gastrique est ajoute pour aider la digestion. •Nourriture dans l’estomac qui est partiellement digérer et mélanger avec l’acide est appeler “chyme”.

Intestin grele•Après l’estomac, la nourriture entre le duodénum, le premier partie du intestin grêle.• Puis il entre le jéjunum et puis le iléon (le dernier partie de l’intestin grêle).•Dans l’intestin grêle, la bile (produit dans le foie et emmagasiner dans la vésicule biliaire), les enzymes pancréatique, et d’autres enzymes produit par les murs de l’intestin grêle aide a briser la nourriture.

Le Gros Intestin•Après l’intestin grêle, la nourriture entre le gros intestin. Dans l’intestin, l’eau et les électrolytes (le sel) sont enlever du nourriture et retourner au sang. •Plusieurs microbes (bactérie etc.) aide le digestion dans le gros intestin.•Le premier partie de l’intestin est appeler caecum (l’appendice est connecter a le caecum). •La nourriture voyage en haute dans le colon ascendant, puis a travers l’abdomen dans le colon transverse et ensuite descend le colon descendant sur l’autre cote du corps.•Finalement, ca passe a travers le colon sigmoïde.

Le fin du processus

• Les déchets solides sont emmagasiner dans le rectum jusqu’au temps qu’il peut être évacuer par l’anus.

L’ABSORPTION et L’ABSORPTION et TRANSPORT des TRANSPORT des NUTRIMENTSNUTRIMENTS

Digested molecules of food, as well as water and Digested molecules of food, as well as water and minerals from the diet, are absorbed from the minerals from the diet, are absorbed from the cavity of the upper small intestine. Most cavity of the upper small intestine. Most absorbed materials cross the mucosa into the absorbed materials cross the mucosa into the blood and are carried off in the bloodstream to blood and are carried off in the bloodstream to other parts of the body for storage or further other parts of the body for storage or further chemical changechemical change

Hydrates de Carbone• Digestible carbohydrates are broken

into simpler molecules by enzymes in the saliva, in juice produced by the pancreas, and in the lining of the small intestine.

• Starch is digested in two steps: • First, an enzyme in the saliva and pancreatic

juice breaks the starch into molecules called maltose; then an enzyme in the lining of the small intestine (maltase) splits the maltose into glucose molecules that can be absorbed into the blood.

• Glucose is carried through the bloodstream to the liver, where it is stored or used to provide energy for the work of the body.

ProteinProtein Protein is digested by enzymes before Protein is digested by enzymes before

they can be used to build and repair body they can be used to build and repair body tissues. tissues.

An enzyme in the juice of the stomach An enzyme in the juice of the stomach starts the digestion of swallowed protein. starts the digestion of swallowed protein.

Further digestion of the protein is Further digestion of the protein is completed in the small intestine. Here, completed in the small intestine. Here, several enzymes from the pancreatic juice several enzymes from the pancreatic juice and the lining of the intestine carry out and the lining of the intestine carry out the breakdown of huge protein molecules the breakdown of huge protein molecules into small molecules called amino acids. into small molecules called amino acids.

LipidsLipids The first step in digestion of a fat is to The first step in digestion of a fat is to

dissolve it into the watery content of the dissolve it into the watery content of the intestinal cavity. intestinal cavity.

The bile acids produced by the liver act as The bile acids produced by the liver act as natural detergents to dissolve fat in water natural detergents to dissolve fat in water and allow the enzymes to break the large and allow the enzymes to break the large fat molecules into smaller molecules, some fat molecules into smaller molecules, some of which are fatty acids and cholesterol.of which are fatty acids and cholesterol.

The bile acids combine with the fatty acids The bile acids combine with the fatty acids and cholesterol and help these molecules and cholesterol and help these molecules to move into the cells of the mucosa. to move into the cells of the mucosa.

The blood carries the fat to storage depots The blood carries the fat to storage depots in different parts of the body.in different parts of the body.

VitaminesVitamines Another vital part of our food that is Another vital part of our food that is

absorbed from the small intestine is the absorbed from the small intestine is the class of chemicals we call vitamins. class of chemicals we call vitamins.

The two different types of vitamins are The two different types of vitamins are classified by the fluid in which they can be classified by the fluid in which they can be dissolved:dissolved:

water-soluble vitamins (all the B vitamins water-soluble vitamins (all the B vitamins and vitamin C) and and vitamin C) and

fat-soluble vitamins (vitamins A, D, and fat-soluble vitamins (vitamins A, D, and K).K).