Download Directed Reading: Digestive System

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Directed Reading A
Section: The Digestive System
______ 1. What is the digestive system?
a. the liver, pancreas, and small intestine
b. a group of organs that work together to break down food
c. the large intestine, gallbladder, and esophagus
d. a group of veins and arteries that work together to digest food
DIGESTIVE SYSTEM AT A GLANCE
______ 2. Which of the following organs is NOT part of the digestive tract?
a. stomach
b. pharynx
c. large intestine
d. kidneys
3. Food passes through some of the organs of the digestive system but not
others. Which organs does food NOT pass through?
BREAKING DOWN FOOD
______ 4. What are the two main kinds of digestion?
a. mechanical and chemical
b. mechanical and liquid
c. mechanical and solid
d. mechanical and heat
5. The kind of digestion that takes place when you chew your
food is
.
6. When your body breaks down food into nutrients,
digestion takes place.
7. The major types of nutrients are
, fats,
and proteins.
8. What substances cut up the protein chains?
9. Proteins are made up of chains of smaller molecules
called
.
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The Digestive and Urinary Systems
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Directed Reading A continued
DIGESTION BEGINS IN THE MOUTH
10. Why is chewing important?
For each kind of tooth listed, write whether it shreds, grinds, or mashes food.
11. premolars
12. incisors
13. canines
14. molars
15. As you chew your food, it is mixed with
.
16. Saliva changes complex carbohydrates into
,
which are easier to digest.
17. How does the food get from your mouth to your throat?
18. What is the function of the esophagus?
THE HARSH ENVIRONMENT OF THE STOMACH
19. What does the stomach do?
20. What do glands in the stomach produce?
21. What happens to most of the bacteria that you swallow with your food?
22. When the food moves out of the stomach, it is a soupy mixture
called
.
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Directed Reading A continued
23. Where does the chyme go when it leaves the stomach?
THE PANCREAS AND SMALL INTESTINE
24. What organ makes fluid that protects the small intestine from the acid in the
chyme?
25. The pancreas produces
to regulate blood sugar.
26. Why is the small intestine called “small”?
27. What do the villi in the small intestine do?
THE LIVER AND GALLBLADDER
______28. Which of the following is NOT a job of the liver?
a. It stores bile.
b. It stores nutrients.
c. It breaks down toxins.
d. It breaks up fat.
29. What is the job of the gallbladder?
30. What does bile do?
31. Which organ breaks down chemicals in the body such as alcohol and drugs?
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Directed Reading A continued
THE END OF THE LINE
______32. Which of the following is NOT a job of the large intestine?
a. absorbing water
b. producing fiber
c. producing feces
d. storing excess material
33. What is fiber?
34. How does solid waste, or feces, leave the body?
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TEACHER RESOURCE
Answer Key
Directed Reading A
34. It is stored in the rectum until it is
expelled through the anus.
SECTION: THE DIGESTIVE SYSTEM
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
SECTION: THE URINARY SYSTEM
B
D
pancreas, liver, gallbladder
A
mechanical
chemical
carbohydrate
enzymes
amino acids
When you chew your food, you break
it into small, slippery pieces. These
pieces are easier to swallow. They are
also easier to digest.
mashing
shredding
shredding
grinding
saliva
simple sugars
The tongue pushes it in.
It squeezes food into the stomach.
The stomach squeezes food with
muscular contractions. This is
mechanical digestion. The stomach
also mixes the food with digestive
juices. This is chemical digestion.
acid and enzymes
It is killed by stomach acid.
chyme
the small intestine
pancreas
hormones
It is small in diameter.
absorb nutrients
A
It stores bile.
Bile breaks large fat droplets into
small droplets so they can be digested
more easily.
liver
B
It is another name for a carbohydrate
called cellulose, which is found in
fruits and vegetables. Humans cannot
digest fiber.
1. C
2. It removes waste products from the
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
blood.
carbon dioxide and ammonia
B
A
They clean, or filter, the blood.
a harmful substance containing
nitrogen
B
to keep water levels in balance, otherwise your body would swell up
When you’re thirsty, ADH keeps your
body from losing more water through
urine. It signals the kidneys to take
water from the nephrons and return it
to the bloodstream.
It causes the kidneys to make more
urine. This decreases the amount of
water in your blood.
B
through the urethra
damage to nephrons can prevent normal kidney functioning and can lead to
kidney disease
Directed Reading B
SECTION: THE DIGESTIVE SYSTEM
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
B
C
D
A
mechanical
chemical
amino acids
enzymes
C
A
C
B
saliva
tongue
esophagus
stomach
enzymes
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The Digestive and Urinary Systems