Download The Body`s Transport System

Name
Date
Circulation
■
Class
Adapted Reading and Study
The Body’s Transport System
(pages 534–543)
The Cardiovascular System
(pages 534–535)
Key Concept: The cardiovascular system carries
needed substances to cells and carries waste
products away from cells. In addition, blood contains
cells that fight disease.
• The cardiovascular system is made up of the heart,
blood vessels, and blood. The heart pumps blood
through the blood vessels.
• Blood carries oxygen and other needed materials to all
of the body’s cells. Blood also picks up wastes, such as
carbon dioxide, from the cells.
• Some cells in blood kill germs. The cells fight disease
and help you get well.
Answer the following questions. Use your textbook and the
ideas above.
1. The system that is made up of the heart, blood vessels,
and blood is the
system.
2. Circle the letter of each job of the cardiovascular
system.
a. carries materials to cells
b. fights disease
c. picks up wastes from cells
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242
Name
Date
Circulation
■
Class
Adapted Reading and Study
The Heart
(pages 536–537)
Key Concept: Each time the heart beats, it pushes
blood through the blood vessels of the cardiovascular
system. The right side of the heart is completely
separated from the left side by a wall of tissue called
the septum. Each side has two compartments, or
chambers—an upper chamber and a lower chamber.
• The heart is a hollow organ about the size of a fist. It is
mostly made of muscle. The heart is in the center of the
chest.
• The heart is separated into a left side and a right side.
Each side of the heart is divided into an upper and lower
“room,” or chamber. The upper chamber on each side is
called the atrium (AY tree um) (plural atria). The lower
chamber on each side is called the ventricle.
• With each beat of the heart, muscles in the heart pump
blood by contracting. First, both atria contract. This
squeezes blood out of the atria and into the ventricles.
Then, both ventricles contract. This squeezes blood out
of the ventricles and into blood vessels.
• A valve is a flap of tissue over a hole that lets blood flow
through the hole in just one direction. There are two
valves in each side of the heart.
• How fast your heart beats is controlled by a group of
cells in the heart called the pacemaker.
Answer the following questions. Use your textbook and the
ideas above.
3. The organ that pumps blood throughout the body is the
.
heart beats is called the
.
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Circulation
4. A group of cells in the heart that controls how fast the
Name
Date
Circulation
■
Class
Adapted Reading and Study
5. Fill in the blanks in the table comparing the upper
chambers and the lower chambers of the heart.
Chambers of the Heart
Name of Chamber
What It Does
a.
pumps blood into a
ventricle
b.
pumps blood into a
blood vessel
6. The diagram below shows the heart and its four
chambers. When the heart beats, which two chambers
contract first? Circle the letter of the correct answer.
a. A and B
The Heart
b. C and D
c. A and C
B
A
D
C
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244
Name
Date
Circulation
■
Class
Adapted Reading and Study
Two Loops
(pages 538–539)
Key Concept: In the first loop, blood travels from the
heart to the lungs and then back to the heart. In the
second loop, blood is pumped from the heart
throughout the body and then returns again to the
heart.
• After leaving the heart, blood travels through arteries.
Arteries are blood vessels that carry blood away from
the heart.
• From arteries, blood flows into capillaries. Capillaries
are tiny blood vessels with very thin walls. In capillaries,
materials are passed back and forth between the blood
and body cells.
• From capillaries, blood flows into veins. Veins are blood
vessels that carry blood back to the heart.
• The right ventricle of the heart pumps blood to the
lungs. In the lungs, the blood drops off wastes and picks
up oxygen. From the lungs, the blood returns to the
heart. This path of the blood is called the first loop, or
loop one.
• The left ventricle of the heart pumps blood to the rest of
the body. The blood leaving the heart is full of oxygen.
The blood drops off oxygen and picks up wastes at the
body cells. Then the blood returns to the heart. This path
of the blood is called the second loop, or loop two.
Answer the following questions. Use your textbook and the
ideas above.
7. Is the following sentence true or false? Blood flows
through the body in one large loop.
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245
Name
Date
Circulation
■
Class
Adapted Reading and Study
8. Fill in the blanks in the table comparing different kinds
of blood vessels.
Kinds of Blood Vessels
Kind of Blood Vessel
What It Does
Artery
carries blood away
from the heart
a.
passes materials
between blood and
body cells
b.
carries blood back to
the heart
9. The diagram shows how blood flows through the body.
In which loop—loop one or loop two—does blood travel
from the heart to the body and back to the heart again?
Loop One
Arteries
to lungs
Veins from
lungs
Right
atrium
Left
atrium
Veins
from body
Artery
to body
Right
ventricle
Left
ventricle
Loop Two
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246
Name
Date
Circulation
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Class
Adapted Reading and Study
Arteries
(pages 540–541)
Key Concept: When blood leaves the heart, it travels
through arteries. The walls of arteries are generally
very thick. In fact, artery walls consist of three cell
layers.
• Every time your heart beats, a spurt of blood is forced
through the arteries. The spurt of blood pushes against
the artery walls. The artery walls must be thick and
strong to withstand the force of the spurting blood.
• The middle layer of artery walls is made of muscles.
These muscles help control the flow of blood by
changing the width of the arteries. When more blood is
needed, the muscles relax and the arteries get wider.
When less blood is needed, the muscles contract and
the arteries get narrower.
Answer the following questions. Use your textbook and the
ideas above.
10. Is the following sentence true or false? When blood
leaves the heart, it travels through veins.
11. The drawing shows the three layers of an artery wall.
What is the layer labeled B made of?
Artery
A
B
C
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247
Name
Date
Circulation
■
Class
Adapted Reading and Study
Capillaries
(page 541)
Key Concept: In the capillaries, materials are
exchanged between the blood and the body’s cells.
Capillary walls are only one cell thick.
• Capillary walls are very thin. Many materials can pass
easily through the thin capillary walls.
• Materials such as oxygen and nutrients pass from the
blood into the body’s cells. Waste materials travel in the
opposite direction—from the body’s cells into the blood.
Answer the following question. Use your textbook and the
ideas above.
12. Circle the letter of each sentence that is true about
capillary walls.
a. The walls are very thick.
b. The walls are one cell thick.
c. The walls allow many materials to pass through.
Veins
(page 542)
Key Concept: After blood moves through capillaries, it
enters larger blood vessels called veins, which carry
blood back to the heart. The walls of veins, like those
of arteries, have three layers, with muscle in the
middle layer.
• The walls of veins also have three cell layers. But, the
walls of veins are not as thick as the walls of arteries.
• By the time blood enters veins, the blood has very little
force. So, the walls of veins do not need to be as thick
and strong as the walls of arteries.
• Veins need help to keep the blood moving. When leg
muscles contract, they squeeze the veins in the legs.
This helps push the blood along. Some veins also have
valves. Valves in veins keep blood flowing in just one
direction.
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248
Name
Date
Circulation
■
Class
Adapted Reading and Study
Answer the following questions. Use your textbook and the
ideas on page 248.
13. Blood flows from capillaries into
.
14. Circle the letter of a reason why blood keeps flowing
through veins.
a. Blood in veins has a lot of force.
b. Vein walls are one cell thick.
c. Contractions of leg muscles squeeze veins.
Blood Pressure
(pages 542–543)
Key Concept: Blood pressure is caused by the force
with which the ventricles contract.
• When the ventricles contract, blood spurts out of the
heart and into the arteries. The spurting blood pushes
against the artery walls. The force of blood against the
walls of the arteries is called blood pressure.
• An instrument can measure blood pressure. Blood
pressure is given as two numbers, written like a fraction.
For example, a normal blood pressure is 120/80.
Answer the following questions. Use your textbook and the
ideas above.
15. Is the following sentence true or false? Blood pressure
is the force of blood against artery walls.
16. Circle the letter of the numbers that show a normal
blood pressure.
a. 120/80
b. 80/120
c. 80/200
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249