Revising the heart
Bill Indge
Revising the heart
In your revision, you need to:
Learn the
facts
Practise the
skills
Master
examination
technique
Revising the heart
Learning the facts
Right atrium
Right ventricle
Left atrium
Left ventricle
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Right atrium
Right ventricle
Left atrium
Left ventricle
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Pulmonary artery
Vena cava
Right atrium
Right ventricle
Aorta
Pulmonary vein
Left atrium
Left ventricle
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Pulmonary artery
Vena cava
Right atrium
Aorta
Pulmonary vein
Left atrium
Right
atrioventricular
valve
Left
semilunar
valve
Right ventricle
Left ventricle
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Sinoatrial node
(SAN)
Atrioventricular node
(AVN)
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Sinoatrial node
(SAN)
Atrioventricular node
(AVN)
Bundle of His
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Introducing tariff values
• Look through your specification for
the ‘stories’ you might be expected to
tell.
• Use past papers to help you to decide
how many marks a question on a
particular topic is likely to be worth. Add
one for luck.
• Summarise the topic in the appropriate
number of bullet points.
Revising the heart
• Look through your specification for the ‘stories’
you might be expected to tell.
The structure and function of the heart
Myogenic stimulation of the heart and transmission of the
subsequent wave of electrical activity
Roles of the sinoatrial node, atrioventricular node and bundle
of His
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• Use past papers to help you to decide how many
marks a question on a particular topic is likely to
be worth.
Explain how a heart beat is initiated and
coordinated.
(6 marks)
• Add one for luck
7 marks
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• Summarise the topic in the appropriate number of
bullet points.
Controlling the heartbeat
• Sinoatrial node
• Myogenic and beats spontaneously
• Impulse spreads over surface of atria
• Atria contract, forcing blood into ventricles
• Delay at atrioventricular node
• Atria empty before ventricles contract
• Impulse goes to base of ventricles and
ventricle contracts from base upwards
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The table shows the pressures in the left atrium, left ventricle
and aorta during a cardiac cycle.
Pressure/kPa
Stage
Left atrium
Left ventricle
Aorta
1
0.5
0.4
10.6
2
1.2
0.7
10.6
3
0.3
6.7
10.6
4
0.4
17.3
16.0
5
0.8
8.0
12.0
Give the number of one stage where:
a) blood flows into the aorta
b) The valve between the atrium and the ventricle is open
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Aorta
Give the number of one stage
where blood flows into the
aorta.
For blood to flow
from the left
ventricle to the
aorta, the pressure
in the ventricle
Left
must be higher than
semilunar
the pressure in the
valve
aorta.
Left
ventricle
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Stage
Pressure/kPa
Left atrium
Left ventricle
Aorta
1
0.5
0.4
10.6
2
1.2
0.7
10.6
3
0.3
6.7
10.6
4
0.4
17.3
16.0
5
0.8
8.0
12.0
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Give the number of one stage
where the valve between the
atrium and the ventricle is open.
Left atrium
Left
atrioventricular
valve
Left ventricle
If the valve
is open, the
pressure in
the left
atrium must
be higher
than the
pressure in
the ventricle.
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Stage
Pressure/kPa
Left atrium
Left ventricle
Aorta
1
0.5
0.4
10.6
2
1.2
0.7
10.6
3
0.3
6.7
10.6
4
0.4
17.3
16.0
5
0.8
8.0
12.0
Revising the heart
Applying your knowledge
AO2 Candidates should be able to
(b) apply scientific knowledge and processes to unfamiliar
situations.
Remember: you may not have seen the wrapping before but
you will be familiar with what is inside.
The context may be new but the biology will be familiar.
Revising the heart
A hole in the heart is caused when the wall between the right atrium
and the left atrium does not close properly when the heart is
developing. This leaves a hole through which blood can pass between
the two atria.
1 Use your knowledge of pressure to explain why blood flows from the
left atrium to the right atrium.
2 The blood in the right atrium of a person with a hole in the heart is
different in its oxygen concentration from the blood in the right atrium
of a healthy person.
(a) In what way is it different?
(b) Explain what causes this difference.
3 The blood pressure in the pulmonary arteries of a person with a hole
in the heart is different from that in the pulmonary arteries of a
healthy person.
(a) In what way is it different?
(b) Explain what causes this difference.
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• The material used in this question is not on your
specification.
• The question will contain all the information you need so
read it carefully.
A hole in the heart is caused when the wall between the right
atrium and the left atrium does not close properly when the
heart is developing. This leaves a hole through which blood can
pass between the two atria.
• The situation may be new but the biology will be familiar.
It is about the heart and blood flow.
So, don’t panic
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Hole in the heart
Right atrium
Left atrium
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1 Use your knowledge of
pressure to explain why
blood flows from the left
atrium to the right atrium.
(2 marks)
R
L
• Blood flows from high
pressure to low pressure;
• Blood pressure higher in
left atrium;
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R
L
2 The blood in the right atrium
of a person with a hole in the
heart is different in its oxygen
concentration from the blood in
the right atrium of a healthy
person.
(a) In what way is it different?
(1 mark)
(b) Explain what causes this
difference.
(2 marks)
(a) Has a higher oxygen
concentration;
(b) Mixed with blood from
left atrium
Which is coming from
lungs;
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R
L
3 The blood pressure in the
pulmonary arteries of a person
with a hole in the heart is
different from that in the
pulmonary arteries of a healthy
person.
(a) In what way is it different?
(1 mark)
(b) Explain what causes this
difference.
(1 mark)
(a) Has a higher pressure;
(b) Contains additional
blood from left atrium;
Revising the heart
Check with your specification and
learn what you need to learn
Find some past papers and practise
the skills
Graphs, tables and
data handling
Applying your
knowledge to new
situations