Download The heart by boardworks

Contents
The Heart
Structure of the heart
Valves in the heart
How the heart pumps blood
Summary quiz
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© Boardworks Ltd 2004
The structure of the heart – exterior
The heart pumps blood around the circulatory system.
What is the heart made of?
muscle
tissue
The heart is made of muscle and keeps pumping blood
around your body, even when you are asleep!
What do the blood vessels on the outside of the heart do?
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The heart needs blood too!
The heart is full of blood but also needs its own blood
supply so that the muscle can keep pumping.
muscle
tissue
blood vessels
supply blood
to muscle tissue
The blood vessels on the outside of the heart carry
oxygen-rich blood to the heart muscle cells.
Oxygen-poor blood is then carried away from these
cells by outer blood vessels and back into the heart.
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The structure of the heart – interior
The inside of the heart is divided into two sections to keep
oxygen-rich and oxygen-poor blood separate.
Each side of the heart is also divided into two sections.
right side
of the heart
left side
of the heart
Each section of the heart is called a chamber.
How many chambers are there?
4
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The chambers of the heart
The four chambers of the heart have special names:
An upper chamber is called an atrium (plural atria).
right
atrium
left
atrium
right
ventricle
left
ventricle
A lower chamber is called a ventricle.
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What do atria and ventricles do?
The chambers of the heart have different functions.
blood to
the lungs
blood from
the body
blood to
the body
blood from
the lungs
The atria collect blood that enters the heart.
The ventricles pump blood out of the heart.
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Inside the heart – labels
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Inside the heart – labelling activity
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Chambers of the heart – activity
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Contents
The Heart
Structure of the heart
Valves in the heart
How the heart pumps blood
Summary quiz
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Preventing backflow
Blood always flows in the same direction as it moves
through the heart during each circulation of the body.
Why is it important that blood does not flow backwards?
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Heart valves
The chambers of the heart are separated by valves
which prevent blood from flowing in the wrong direction.
valve leading
out of
right ventricle
valve between
right atrium and
right ventricle
valve leading
out of
left ventricle
valve between
left atrium and
left ventricle
There are valves between the atria and the ventricles…
…and there are valves leading out of the ventricles.
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Naming the heart valves
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Contents
The Heart and Circulatory System
The circulatory system
Structure of the heart
Valves in the heart
How the heart pumps blood
Summary quiz
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© Boardworks Ltd 2004
How does the heart pump blood?
Imagine the force needed
to squeeze a tennis ball.
That’s how much force
the heart uses to pump
blood around the body!
How does the heart produce
enough force to keep doing
this 24 hours a day?
The heart can pump blood
because it is made of muscle.
Muscle tissue works by
contracting (squeezing)
and relaxing.
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How does the heart pump blood?
All the parts of the heart on
either side, work together
in a repeated sequence.
The two atria contract and
relax; then the two ventricles
contract and relax.
This is how blood moves
through the heart and is
pumped to the lungs and
the body.
One complete sequence of
contraction and relaxation is
called a heartbeat.
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Heartbeat animation
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How many heartbeats?
If your heart beats at an average rate of 70 times
per minute, how many heartbeats are there…
…in one hour?
70 x 60 =
4, 200
…in one day?
4, 200 x 24 =
100, 800
…in one year?
100, 800 x 365 =
36, 792, 000
…in 70 years?
36, 792, 000 x 70 =
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2, 575, 440, 000
© Boardworks Ltd 2004
The sequence of a heartbeat
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Journey of blood around the body
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Contents
The Heart and Circulatory System
The circulatory system
Structure of the heart
Valves in the heart
How the heart pumps blood
Summary quiz
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Multiple-choice quiz
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© Boardworks Ltd 2004