Download 33_1a

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Class
Date
33.1 The Circulatory System
Lesson Objectives
Identify the functions of the human circulatory system.
Describe the structure of the heart and explain how it pumps blood through the body.
Name three types of blood vessels in the circulatory system.
BUILD Vocabulary
A. The chart below shows key terms from the lesson with their definitions. Complete the chart by
writing a strategy to help you remember the meaning of each term. One has been done for you.
How I’m Going to Remember the
Meaning
Term
Definition
Atrium
The upper chamber of the heart
where blood enters from the body
Capillary
The smallest blood vessels
Myocardium
The muscle layer in the heart that
contracts to pump blood
throughout the body
Vein
A vessel that carries blood back
to the heart
Ventricle
The lower chamber of the heart
where blood is pumped out
A vein is like a vine climbing up the legs.
It carries blood back to the heart.
B. As you work through this lesson, you may find these terms in the activities. When you need to
write a key term or a definition, highlight the term or the definition.
BUILD Connections
A City’s Transportation System An analogy takes two
things that seem to be different and shows how they can be
similar.
1. Complete the sentence. If streets are like the circulatory
system, a city is like the
.
2. Using the analogy, explain to a partner how the circulatory
system transports nutrients, oxygen, and wastes.
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BUILD Understanding
Preview Visuals Before you read the lesson, look at the visual called The Heart. In the left
column of the chart, complete the list of the heart’s largest structures. As you read, fill in the right
column with the function of each structure.
Structure
Function
aorta
carries oxygen-rich blood to the body
superior vena cava
brings oxygen-poor blood from the upper body
to the right atrium
valves
prevent blood from flowing backward
right atrium
inferior vena cava
brings oxygen-poor blood from the lower body
to the right atrium
accepts oxygen-rich blood from the lungs
left ventricle
separates the two sides of the heart
The Heart
Heart Structure The human heart
has four chambers: right atrium,
right ventricle, left atrium, and left
ventricle. Blood flows from the body
into the right atrium.
Follow the directions.
1. Color the left atrium orange.
2. Color the left ventricle red.
3. Color the right atrium yellow.
4. Color the right ventricle blue.
Answer the questions. Circle the correct answer.
5. Where does oxygen-rich blood from the lungs enter the heart?
left atrium
left ventricle
6. What part of the heart pumps oxygen-poor blood to the lungs?
right atrium
right ventricle
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The Heart
Circulation The human circulatory system moves blood through two primary pathways. One
connects the heart and lungs. The other connects the heart and the rest of the body. The diagram
below shows the main parts of the circulatory system.
Follow the directions.
1. Draw arrows to show how blood moves through the circulatory system.
Answer the questions. Circle the correct answer.
2. Through which blood vessel does blood return to the heart from the head and arms?
inferior vena cava
superior vena cava
3. Which pulmonary blood vessel carries oxygen-rich blood?
pulmonary artery
pulmonary vein
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