Cardiovascular system 9th grade

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Circulation and
Respiration
The Cardiovascular
System

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Two Types of Circulation
The Cardiovascular System
The cardiovascular system
Structure of the heart
Blood Vessels
Cardiovascular Problems
Contents
Summary quiz

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How do substances move around the body?
Read pg. 546, -Your cardiovascular system-
and summarize the functions and the parts of
the cardiovascular system.

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The Cardiovascular System

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The Cardiovascular System
The Heart
Create the
pressure necessary
to move the blood
Blood
Fluid that delivers
nutrients and
oxygen to the
cells
Blood Vessels
Transports blood
throughout the
human body.

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The Cardiovascular System
• amino acids
• glucose
Maintain Homeostasis
Carry Nutrients
Remove Wastes
Chemical Signals
Regulates
Temperature
• CO2
• Urea
• Insulin
• Estrogen
• Testosterone
• Melatonine

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Two Types of Circulation
The Cardiovascular System
The cardiovascular system
Structure of the heart
Blood Vessels
Cardiovascular Problems
Contents
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?
The heart is made of muscle and keeps pumping blood
around your body, even when you are asleep!
muscle
tissue
What do the blood vessels on the outside of the heart do?
blood vessels
supply blood
to muscle tissue

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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.
oxygen-poor
blood
right side
of the heart
oxygen-rich
blood
left side
of the heart
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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Inside the heart
right side
of the heart
left side
of the heart

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The arrangement of the circulatory system means that these
two types of blood do not mix. Why is this important?
Two types of blood
The circulatory system carries two types of blood:
oxygen-rich
blood
c
oxygen-poor
blood
blood travelling
to the body cells
high oxygen content
low carbon dioxide
content
blood travelling
away from the body cells
low oxygen content
high carbon dioxide
content

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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.
Each section of the heart is called a chamber.
How many chambers are there?
right side
of the heart
left side
of the heart
4

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The chambers of the heart
The four chambers of the heart have special names:
A lower chamber is called a ventricle.
An upper chamber is called an atrium (plural atria).
right
ventricle
right
atrium
left
ventricle
left
atrium

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What do atria and ventricles do?
The chambers of the heart have different functions.
The atria collect blood that enters the heart.
The ventricles pump blood out of the heart.
blood to
the body
blood from
the body
blood to
the lungs
blood from
the lungs

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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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The chambers of the heart are separated by valves
which prevent blood from flowing in the wrong direction.
Heart valves
There are valves between the atria and the ventricles…
…and there are valves leading out of the ventricles.
valve between
right atrium and
right ventricle
valve between
left atrium and
left ventricle
valve leading
out of
right ventricle
valve leading
out of
left ventricle

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How are valves held in place?
The valves between the atria and ventricles are connected
to the inner walls of the heart by tough tendons.
valve open

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How are valves held in place?
The tendons allow the valves to close and hold the valve
flaps in place. They prevent the valves from flipping up
and turning inside out. Why is this important?
valve open valve closed

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How do valves work?
A valve acts like a door that only opens in one direction.
If the door is held by someone at a fixed point, only the arm
moves as the door opens and closes.
When the door is closed the arm is fully extended, so the
door can only be opened in one direction.

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How do valves work?
A valve acts like a door that only opens in one direction.
In the heart, the tendons holding the valve are like the
arm holding the door.
One end of each tendon is fixed to the wall of the heart
and so the valve can only open in one direction.

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Two Types of Circulation
The Cardiovascular System
The cardiovascular system
Structure of the heart
Blood Vessels
Cardiovascular Problems
Contents
Summary quiz

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Blood travels throughout the body in hollow tubes called
blood vessels. There are three types:
Blood Vessels
ARTERIES
 Carry blood away from
the heart.
 Thick and highly elastic
walls with a layer of
smooth muscle.
 Expansion/contraction
of artery walls provides
additional pumping.
 When you measure
your pulse, what you
feel is the rhythmic
expansion and
contraction of an artery
as blood moves
through it.
CAPILLARIES
 A network of capillaries
joins the arteries with
all the body.
 One-cell-thick
 Is where gases,
nutrients, and other
materials are
transferred from blood
to cells vice versa.
 No cell in the body is
more than three or four
cells away from a
capillary
VEINS
 Carry blood toward the
heart
 Thinner walls than
arteries & larger inner
circumference.
 Not elastic, and they
cannot contract (need
contraction of muscles).
 Have one-way valves
that prevent the blood
from flowing backward.

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Blood travels throughout the body in hollow tubes called
blood vessels. There are three types:
Blood Vessels

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Blood Vessels

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Two Types of Circulation
The Cardiovascular System
The cardiovascular system
Structure of the heart
Blood Vessels
Cardiovascular Problems
Contents
Summary quiz

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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? body’s
cells
body’s
cells

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The oxygen-poor
blood needs to lose
the carbon dioxide and
pick up more oxygen.
How does it do this?
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.
body’s
cells
body’s
cells

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lungslungs
Where does this
oxygen-rich blood
then travel to?
How does blood circulate around the body?
Next, the right side
of the heart pumps
oxygen-poor blood
to the lungs.
In the lungs the blood
gets rid of the waste
carbon dioxide and
collects more oxygen.
body’s
cells
body’s
cells

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The oxygen-rich
blood then returns
to the left side of the
heart.
This completes the
blood’s journey
around the body.
Why is the journey
of blood through the
circulatory system
called a double
circulation?
How does blood circulate around the body?
body’s
cells
body’s
cells
lungslungs

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During one complete
circuit of the body,
blood passes through
the heart twice.
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?
A double circulatory system
body’s
cells
body’s
cells
lungslungs

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The Heart and Circulatory System
The circulatory system
Structure of the heart
How the heart pumps blood
Valves in the heart
Summary quiz
Contents
Summary quiz

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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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What does a doctor hear when they listen to a patients’ heart?
Listening to a beating heart: lub-dub
The “lub” is caused by
the closing of the valves
leading to the ventricles.
The “dub” is caused by
the closing of the valves
leading out of the heart.
lub-dub,
The sound of a heartbeat is the sound of the heart valves.
lub-dub, lub-dub, lub-dub, lub-dub, lub-dub…

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Measuring a beating heart
You can measure how
fast your heart is beating
by taking your pulse.
Each pulse that you feel
is due to the pressure of
blood leaving the heart as
the left ventricle contracts.
Place the fingertips of one
hand on the opposite wrist,
where an artery passes
near the surface of the skin.
What is your heart rate,
in beats per minute,
right now?

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…in one hour?
…in one day?
…in one year?
…in 70 years?
How many heartbeats?
If your heart beats at an average rate of 70 times
per minute, how many heartbeats are there…
70 x 60 =
4,200 x 24 =
100,800 x 365 =
36,792,000 x 70 =
100,800
36,792,000
2,575,440,000
4,200

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Two Types of Circulation
The Cardiovascular System
The cardiovascular system
Structure of the heart
Blood Vessels
Cardiovascular Problems
Contents
Summary quiz

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The two sides of the heart

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Inside the heart – labelling activity

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Inside the heart – labels

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Chambers of the heart – activity

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The sequence of a heartbeat

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Journey of blood around the body

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Multiple-choice quiz