Download Directed Reading: Urinary System

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Directed Reading A
Section: The Urinary System
______ 1. What is excretion?
a. the process of digesting food
b. the process of breathing
c. the process of removing waste from the body
d. the process of adding nutrients to the body
2. What is the job of the urinary system?
CLEANING THE BLOOD
3. What are two examples of wastes that the urinary system removes from the
blood?
THE KIDNEYS AS FILTERS
______ 4. How many kidneys does a person normally have?
a. one
b. two
c. three
d. four
______ 5. Which of the following is the job of the nephrons?
a. They remove wastes from the blood.
b. They produce urea.
c. They produce urine.
d. They clean the kidneys.
6. What do the kidneys do?
7. What is urea?
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Science and Technology
5
The Digestive and Urinary Systems
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Directed Reading A continued
WATER IN, WATER OUT
______ 8. Why do humans sweat?
a. to cleanse the skin
b. to cool the body
c. to produce saliva
d. to control thirst
9. Why does your body need to excrete as much water as it brings in?
10. What does ADH do?
11. What effect does a diuretic have on your body?
URINARY SYSTEM PROBLEMS
______12. Kidney stones are made of which of the following substances?
a. viruses
b. waste materials
c. ADH
d. bacteria
13. How can bacteria get into the bladder and ureters?
14. What can happen if the nephrons are damaged?
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Science and Technology
6
The Digestive and Urinary Systems
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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
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Science and Technology
75
The Digestive and Urinary Systems