Download The Digestive Process Begins

Name
Date
Food and Digestion
■
Class
Adapted Reading and Study
The Digestive Process Begins
(pages 60–65)
Functions of the Digestive System
(pages 60–61)
Key Concept: The digestive system has three main
functions. First, it breaks down food into molecules
the body can use. Then, the molecules are absorbed
into the blood and carried throughout the body.
Finally, wastes are eliminated from the body.
• The digestive system includes the mouth, esophagus,
stomach, small intestine, and large intestine.
• The digestive system breaks down food into tiny pieces
called molecules. The process of breaking down food is
called digestion.
• Digestion includes both mechanical digestion and
chemical digestion. Mechanical digestion breaks chunks
of food into smaller pieces. Chemical digestion breaks
big food molecules into smaller, simpler food molecules.
• After food is digested, food molecules pass from the
digestive system into the blood. This process is called
absorption (ab SAWRP shun).
• Some materials in the digestive system cannot be
absorbed. These materials pass out of the body as
wastes. This process is called elimination.
Answer the following questions. Use your textbook and the
ideas above.
1.
digestion breaks chunks of
food into smaller pieces.
2.
digestion breaks big food
molecules into smaller, simpler food molecules.
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33
Name
Date
Food and Digestion
■
Class
Adapted Reading and Study
3. Draw a line from each term to its meaning.
Term
Meaning
digestion
a. food molecules pass into the blood
absorption
elimination
b. wastes pass out of the body
c. food is broken down into
molecules
4. The picture shows organs of the digestive system. Fill
in the blanks with the names of the organs shown.
Mouth
Esophagus
a.
Large intestine
b.
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34
Name
Date
Food and Digestion
■
Class
Adapted Reading and Study
The Mouth
(pages 62–63)
Key Concept: Both mechanical and chemical
digestion begin in the mouth.
• When you chew, your teeth tear and crush food into
smaller pieces. Chewing starts mechanical digestion.
• Saliva starts chemical digestion. Saliva (suh LY vuh) is
the fluid in your mouth. Saliva breaks big starch
molecules into smaller sugar molecules.
Answer the following question. Use your textbook and the
ideas above.
5. Both mechanical and chemical digestion begin in the
.
The Esophagus
(page 63)
Key Concept: After food enters the esophagus,
contractions of smooth muscles push the food toward
the stomach.
• The esophagus (ih SAHF uh gus) is a muscular tube.
The esophagus connects the mouth to the stomach.
• Muscles of the esophagus squeeze the food through the
tube. The food quickly reaches the stomach.
Answer the following question. Use your textbook and the
ideas above.
6. Circle the letter of each sentence that is true about the
esophagus.
a. Food enters the esophagus from the mouth.
b. Chemical digestion begins in the esophagus.
c. Muscles squeeze food through the esophagus.
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
35
Name
Date
Food and Digestion
■
Class
Adapted Reading and Study
The Stomach
(pages 64–65)
Key Concept: Most mechanical digestion and some
chemical digestion occur in the stomach.
• The stomach is a muscular organ that looks like a
pouch. Stomach muscles squeeze and mix the food in
the stomach. The mixing finishes mechanical digestion.
• The stomach makes digestive juices. These juices
continue chemical digestion.
• By the time food leaves the stomach, it is a thick fluid.
Answer the following questions. Use your textbook and the
ideas above.
7. Is the following sentence true or false? Only chemical
digestion takes place in the stomach.
8. What causes chemical digestion in the stomach? Circle
the letter of the correct answer.
a. saliva
b. stomach muscles
c. digestive juices
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36