Download The Heart and Circulatory System

The Heart and
Circulatory System
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Contents
The Heart and Circulatory System
The circulatory system
Structure of the heart
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How do substances move around the body?
The body has its own transport
system that carries substances
around the body.
Which organs are involved in
this system?
heart
blood vessels
blood
The body’s transport system is
called the circulatory system.
Why is it given this name?
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What is carried by the circulatory system?
Which gases are transported to and from the body’s cells
by the blood flowing in the circulatory system?
carbon
dioxide
oxygen
Oxygen is the gas needed for respiration and is transported
to the body’s cells.
Carbon dioxide is the waste gas produced by respiration
that must be carried away from the body’s cells.
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Two types of blood
The circulatory system carries two types of blood:
oxygen-rich
blood
oxygen-poor
blood
 blood travelling
c
to the body cells
 blood travelling
away from the body cells
 high oxygen content
 low oxygen content
 low carbon dioxide
content
 high carbon dioxide
content
The arrangement of the circulatory system means that these
two types of blood do not mix. Why is this important?
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At the heart of the circulatory system
The heart is the organ at the centre of the circulatory system.
It pumps blood around the body.
How are the two types of blood (oxygen-rich and
oxygen-poor) kept apart inside the heart?
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Inside the heart
The inside of the heart is divided into two sections so that
the two types of blood (oxygen-rich and oxygen-poor)
are kept apart.
right side
of the heart
left side
of the heart
oxygen-poor
blood
oxygen-rich
blood
Remember that the heart is always labelled as if it is in a
body facing you, so the right side of the heart is on the
left of the diagram.
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The two sides of the heart
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How does blood circulate around the body?
Blood is pumped
around the body by
the heart.
It takes about 30
seconds for blood to
go once around the
body.
Starting with the left
side of the heart,
what route does the
blood follow to
complete one circuit
of the body?
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How does blood circulate around the body?
The left side of
the heart pumps
oxygen-rich blood
to the rest of the body.
This blood supplies
the body’s cells with
oxygen.
What gas does the
blood then pick up
from the body’s cells
and where does the
blood go next?
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body’s
cells
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How does blood circulate around the body?
Blood picks up
carbon dioxide from
the body’s cells.
This oxygen-poor
blood then travels
back to the right side
of the heart.
The oxygen-poor
blood needs to lose
the carbon dioxide and
pick up more oxygen.
How does it do this?
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body’s
cells
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How does blood circulate around the body?
Next, the right side
of the heart pumps
oxygen-poor blood
to the lungs.
lungs
In the lungs the blood
gets rid of the waste
carbon dioxide and
collects more oxygen.
Where does this
oxygen-rich blood
then travel to?
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body’s
cells
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How does blood circulate around the body?
The oxygen-rich
blood then returns
to the left side of the
heart.
lungs
This completes the
blood’s journey
around the body.
Why is the journey
of blood through the
circulatory system
called a double
circulation?
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body’s
cells
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A double circulatory system
During one complete
circuit of the body,
blood passes through
the heart twice.
lungs
The heart has two
jobs to do and so the
circulatory system
involves a double
circulation.
What are the two jobs
that the heart carries
out during this double
circulation?
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body’s
cells
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Which way does blood flow?
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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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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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