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