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This is a study guide for our work on the Digestive System.
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THE DIGESTIVE SYSTEM A Study Guide
Mr. Ardito’s Living Environment
The purpose of the Digestive System
To make big things into small things
The Parts of the Digestive System
The Mouth
Teeth grind food into swallowable substance (bolus)
Enzymes in saliva start to break down starches.
Esophagus
Muscular contractions move the bolus to the stomach
These contractions are called peristalsis
No new digestion occurs
Stomach
Stomach is very muscular and churns the food into a paste (chyme).
Stomach makes acid which helps break down proteins.
Small Intestine
No new mechanical digestion takes place.
Enzymes break down proteins, starches, and fats
Nutrients are absorbed into the bloodstream via the villi.
Large Intestine
Undigested food (now called feces)passes into the large intestine.
Water, minerals, and vitamins are reabsorbed.
Anus/Rectum
The rectum stores feces until it is ready to be released.
The anus is the opening through which feces is released.
Types of DigestionPart Mechanical Chemical
Mouth Chewing Enzymes from saliva
Esophagus NoneNone (still
continuing from mouth)
Stomach Churning of FoodAcid from gastric
juice
Small Intestine None Enzymes
Large Intestine NoneReabsorption of
water and minerals
EnzymesEnzymes are chemicals that speed up chemical reactions.
Enzymes used in digestion help break big things into small things.
3 types of enzymes
Proteases - act on proteins
Amylases - act on starch
Lipases - act on fats