The Heart and Cardiac Cycle Question
Booklet
Name………………………………….…..
Target Grade…………………..
Grade achieved……………….
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Unit 1- Woodford County High School
1.
The diagram shows a human heart
(a)
On the diagram, label the position of the atrioventricular node.
(1)
An electro-cardiogram (ECG) is produced by placing electrodes on the chest to
detect electrical changes in the heart.
The diagram shows an ECG and the pressure changes during a human cardiac
cycle.
Pressure
in aorta
Blood
pressure
Pressure in
left ventricle
R
T
P
P
ECG
Q
0
S
0.1
Unit 1- Woodford County High School
0.2
0.3
0.4
Time/seconds
0.5
0.6
0.7
0.8
(b)
(i)
The QRS wave is associated with the spread of electrical activity over the
ventricle. Explain the evidence in the graph which supports this.
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(2)
(ii)
Explain why there is no change in the electrical activity between 0.31s and
0.77s.
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(1)
(c)
(i)
At what time in the cardiac cycle does the aortic semilunar valve open?
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(1)
(ii)
The pressure changes shown in the diagram are on the left side of the heart.
Sketch a curve on the graph to show the pressure changes in the right
ventricle.
(2)
(Total 7 marks)
2.
The cardiac output is the amount of blood one ventricle pumps out per minute.
The table shows the percentage of the cardiac output distributed to various
organs when the body is at rest.
Organ
Percentage of cardiac
output at rest
Bone
5
Brain
15
Heart
5
Kidneys
25
Liver
15
Skin
5
Unit 1- Woodford County High School
(i)
At rest the amount of blood pumped out by a single contraction of one
ventricle is 70 cm3 and the mean heart rate is 72 beats per minute.
Calculate the total volume of blood supplied to the brain per minute.
Show your working.
Answer = ..........................
(2)
(ii)
Prolonged training often results in a decrease in the resting heart rate
although the cardiac output remains the same. How is this decrease
achieved?
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(1)
(Total 3 marks)
3.
(a)
During a cardiac cycle, a wave of electrical activity spreads from the sino-atrial
node. Describe how the spread of this wave of electrical activity results in
(i)
the ventricles only contracting after they have filled with blood;
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(1)
(ii)
the contraction of the ventricles starting at the apex of the heart.
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(1)
Unit 1- Woodford County High School
(b)
The graphs show some of the pressure and volume changes that take place in the
left side of the heart during part of a cardiac cycle.
16
14
Key
12
Pressure/kPa
Aorta
Left ventricle
Left atrium
10
8
6
4
2
0
Time
130
120
Volume of
left ventricle/cm 3
110
100
90
80
70
60
A
B
Time
Using information from the graphs, describe the events which produce the change
in volume of blood in the ventricle between times A and B.
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(3)
(Total 5 mark)
Unit 1- Woodford County High School
4.
a)
The diagram shows a human heart.
Left atrium
Coronary artery
(i)
Use a guideline and label to show the position of the sinoatrial node (SAN).
(1)
(ii)
What is the function of the coronary artery?
.........................................................................................................................
(1)
(b) Impulses spread through the walls of the heart from the SAN. The table shows
the rate of conduction of impulses through various parts of the conducting
tissues.
Rate of conduction / m s–1
Mean distance / mm
From SAN to
atrioventricular node
(AVN) across atrium
1.0
40
Through AVN
0.05
5
From AVN to lower end
of bundle of His
1.0
10
Along Purkyne fibres
in ventricle walls
4.0
–
Part of pathway
Unit 1- Woodford County High School
(i)
Calculate the mean time taken for an impulse to pass from the SAN to the
lower end of the bundle of His. Show your working.
................................... s
(2)
(ii)
Explain the advantage of the slow rate of conduction through the AVN.
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(2)
(iii)
Suggest one advantage of the high rate of conduction in the Purkyne fibres
which carry impulses through the walls of the ventricles.
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.........................................................................................................................
(1)
(c)
How would cutting the nerve connections from the brain to the SAN affect the
beating of the heart?
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...................................................................................................................................
(1)
(Total 8 marks)
Unit 1- Woodford County High School
5.
(a)
The graph shows the changes in pressure which take place in the left
side of the heart.
15
Aorta
10
Pressure/
kPa
Left ventricle
5
Left
atrium
0
0.2
(i)
0.4
0.6
Time/seconds
0.8
1.0
Use the graph to calculate the heart rate in beats per minute. Show your
working.
Answer ..............................
(2)
(ii)
The atrioventricular valve closes at 0.1 seconds.
Explain the evidence from the graph which supports this statement.
.........................................................................................................................
(1)
(b)
The blood pressure in the aorta is higher than in the pulmonary artery.
Explain what causes the blood pressure in the aorta to be higher.
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...................................................................................................................................
(1)
(Total 4 marks)
Unit 1- Woodford County High School
6.
The diagram shows the pathways in the heart for the conduction of electrical impulses
during the cardiac cycle.
(a)
The table shows the blood pressure in the left atrium, the left ventricle and the
aorta at different times during part of a cardiac cycle.
Blood pressure / kPa
(i)
Time / s
Left atrium
Left ventricle
Aorta
0.0
0.5
0.4
10.6
0.1
1.2
0.7
10.6
0.2
0.3
6.7
10.6
0.3
0.4
17.3
16.0
0.4
0.8
8.0
12.0
At which time is blood flowing into the aorta?
......................................................................................................................…
(1)
(ii)
Between which times are the atrioventricular valves closed?
......................................................................................................................…
(1)
(b)
The maximum pressure in the left ventricle is higher than the maximum pressure
in the right ventricle. What causes this difference in pressure?
...................................................................................................................................
(1)
(Total 3marks)
Unit 1- Woodford County High School
7.
Although the heart does have a nerve supply, the role of the nervous system is not to
initiate the heartbeat but rather to modify the rate of contraction. The heart
determines its own regular contraction.
Describe how the regular contraction of the atria and ventricles is initiated and
coordinated by the heart itself.
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(5)
8. (a)During the cardiac cycle the heart fills with blood and then the ventricles contract. The
table gives the filling time and the contraction time at different heart rates.
(i)
Heart rate/beats
per minute
Filling time/seconds
Contraction
time/seconds
39.7
0.37
1.14
49.6
0.38
0.83
71.4
0.38
0.46
81.1
0.38
0.36
87.0
0.39
0.30
Give two conclusions that can be drawn from the figures in the table.
1 ...............................................................................................................
.........................................................................................................................
2 ...............................................................................................................(2)
Unit 1- Woodford County High School
(ii)
Explain how you would use the figures in the table to calculate the
contraction time at a heart rate of 60 beats per minute.
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(2)
(iii)
What additional information would you need in order to find the cardiac
output at a particular heart rate?
.........................................................................................................................
(1)
(b)
The diagram shows variations in blood pressure in different parts of the
circulatory system.
Left ventricle
A
Aorta
Vein
B
Pressure
Time
(i)
Time
Time
Complete the table with ticks to show whether each of the valves is open
or closed at the point indicated with the letter A on the diagram. (2)
Valve located between
left atrium and left ventricle
left ventricle and aorta
right atrium and right ventricle
right ventricle and pulmonary artery
Unit 1- Woodford County High School
Open
Closed
(ii)
A pulse can be felt when the fingers are placed over an artery that is close
to the surface. Explain why a pulse cannot be felt when the fingers are
placed over a vein which is close to the surface.
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.........................................................................................................................
(1)
(iii)
What causes the blood pressure to increase at the point indicated with a
letter B on the diagram?
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(1)
(Total 9 marks)
9.
The diagram shows a section through a human heart.
C
B
A
D
(a)
Which of the blood vessels labelled A to D
(i)
takes blood from the heart to the muscles of the arms and legs;
........................................................................................................................
(1)
(ii)
is a vein which contains oxygenated blood?
.........................................................................................................................
(1)
Unit 1- Woodford County High School
(b)
Is the right ventricle filling with blood or emptying? Give two pieces of evidence
from the diagram to support your answer.
Filling or emptying? ..................................................................................................
Evidence
1 .........................................................................................................................
2 .........................................................................................................................
(2)
The graphs show some changes in pressure and volume during part of a cardiac cycle.
Aorta
Pressure
Ventricle
Volume
of
ventricle
X
(c)
Y
Time
Z
Describe what the graphs show about the pressure and volume in the ventricle
between times X and Y.
...................................................................................................................................
...............................................................................................................................(1)
Unit 1- Woodford County High School
(d)
At point Y, the valve between the aorta and the ventricle opens. Use the
information about pressure on the graph to explain why.
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...................................................................................................................................
(1)
(e)
Explain the changes in the volume of the ventricle between times X and Z.
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(3)
(Total 9 marks)
10.
The graph shows changes in the volume of blood in the left ventricle.
140
120
100
Volume /
cm 3
80
60
40
20
0
0
0.2
0.4
0.6
Time / s
Unit 1- Woodford County High School
0.8
1.0
(a)
Between which times is the left atrium contracting? Give the evidence from the
graph that supports your answer.
Times .........................................................................................................................
Evidence …….............................................................................................................
............……….............................................................................................................
(2)
(b)
Use the graph to calculate.
(i)
the heart rate;
Answer ............................................
(2)
(ii)
stroke volume.
Answer ............................................
(1)
(c)
Describe how you would calculate cardiac output from heart rate and stroke
volume.
............………..............................................................................................................
............………..............................................................................................................
(1)
The table shows the rate of blood flow to some organs when a person is at rest and
during a period of vigorous exercise.
Organ
Rate of blood flow / cm3 minute–1
at rest
(d)
during exercise
Skeletal muscles
1 000
16 000
Kidney
1 200
1 200
Brain
750
Heart muscle
300
1 200
Suggest a value for the rate of blood flow to the brain during exercise.
............………..............................................................................................................
(1)
Unit 1- Woodford County High School
(e)
(i)
The coronary arteries take blood to the muscles in the wall of the heart.
Calculate the ratio of the rate of blood flow into the coronary arteries
during exercise to the rate flowing into these arteries at rest.
Answer.............................................
(1)
(ii)
At rest the rate of flow of blood to the heart muscle is 0.9 cm3 g–1 per
minute.
Calculate the volume of blood 1g of heart muscle would receive in 5
minutes of vigorous exercise.
Answer.............................................
(1)
(Total 9 marks)
Unit 1- Woodford County High School
Mark Scheme
1.
(a)
correct position of AVN; (at the top of Purkyne tissue)
(b)
(i)
pressure in ventricles increasing (so ventricle contracting);
QRS occurs before pressure increase/ventricle contraction/
contracts after S / 0.14s;
2
(ii)
corresponds to time when heart is relaxed/filling with blood/
diastole / not contracting;
1
(i)
0.2s ;
(ii)
line below left ventricle;
in phase with left ventricle; 2
(c)
1
1
[7]
2.
(a)
(i)
70 x 72 = 5040 plus method shown for calculating percentage;
756cm3;
2
(ii) (increase in size of heart) increasing amount of blood pumped out /
Increasing stroke volume;
1
[3]
3.
(a)
(b)
(i)
Delay in spread of electrical activity at AV node/from atria to ventricle;
(ii)
Rapid spread of activity down ventricular septum/to base of ventricles/
along bundle of His/electrical activity travels up from base; 1
1
Ventricle contracts/systole;
Pressure increases in ventricle/pressure in ventricle higher than in aorta;
Valve between ventricle and aorta opens; 3
[5]
4.
(a)
(b)
(i)
guideline to upper part of right atrium;
(ii)
supply oxygen / nutrients to heart muscle / for contraction;
(i)
0.15s = 2 marks;
(working 0.04 + 0.10 + 0.01 = 1 mark)
(allow 1 mark for correct method dividing each distance by rate)
(ii)
(iii)
(c)
delays contraction of ventricles;
until after atria have contracted / ventricles filled;
1
2
rapid contraction of ventricles / both ventricles contract
together / rapid transmission to tip so contraction starts at
bottom of ventricles;
(reject strong contraction) 1
rate of heart beat not adjusted to activity / carries on beating at
Unit 1- Woodford County High School
1
2
constant rate / myogenic, so no effect;
(Accept: rate would increase because parasympathetic normally inhibits)
1
[8]
5.
(a)
(i)
(ii)
(b)
60 ÷ 0.72 – 0.76;
79 – 83; (Correct answer = 2 marks)
2
Ventricular pressure increases above pressure in atrium ;
1
Left ventricle has thicker / more muscle;
1
[4]
6.
(a)
(b)
(i)
0.3 s;
1
(ii)
0.2 - 0.4 s;
1
thicker / more muscle in the left ventricle;
1
[3]
10.
7.
8.
(cardiac) muscle is myogenic;
sinoatrial node/SAN;
wave of depolarisation/impulses/electrical activity (across atria);
initiates contraction of atria
atrioventricular node/AVN;
bundle of His/purkyne tissue spreads impulse across ventricles;
ventricles contract after atria/time delay enables ventricles to fill;
(a)
(i)
(ii)
Filling time stays constant / increases very little /
as heart rate increases;
Decrease in contraction time as heart rate increases;
Allow maximum of 1 mark if no reference to heart rate.
Work out time for one heart beat / one heart beat takes 1 second;
Subtract filling time / 0.38s;
Credit these basic points however determined. If the calculation
has been done, credit any point in method clearly explained.
OR
Plot contraction time against heart rate;
Unit 1- Woodford County High School
[5]
2
(iii)
(b)
Read off value for 60 beats per minute;
2
Stroke volume / volume of blood pumped out at each beat;
1
(i)
2
Valve located between
Open
Closed
Left atrium and left ventricle
Left ventricle and aorta
;
Right atrium and right ventricle
Right ventricle and pulmonary artery
(ii)
(iii)
;
Pressure constant / smooth in vein / only have pressure
surges in artery;
1
Contraction of ventricle / systole / entry of blood into aorta;
1
[9]
9.
(a)
(b)
(i)
B/aorta;
1
(ii)
D/pulmonary vein;
1
Filling because valve between artery and ventricle closed;
Valve between atrium and ventricle/ cuspid valve open;
2
[Note: All answers must be in context of filling.
Answers specifically relating to left side are incorrect.]
(c)
Pressure increases and volume stays constant;
(d)
Pressure in ventricle (becomes) higher than pressure in aorta;
[Or converse]
(e)
1
1
ventricle contracts;
Produces increase in pressure;
Blood leaves venticle/ goes into aorta (and volume falls);
Through open valve;
max 3
[9]
Unit 1- Woodford County High School
10.
(a)
(b)
0.1 – 0.6 seconds;
Volume (in left ventricle) increasing / ventricle filling;
(i)
(ii)
2
2 marks for correct answer of 75 (beats) per minute;
1 mark if heart beat correctly identified as lasting 0.8 seconds;
2
70 cm ;
1
(c)
Multiply them;
1
(d)
750;
Accept a small increase – up to 800 cm
1
(e)
(i)
4 : 1 / 4;
Ratio must be expressed in simplest terms
1
(ii)
18 cm ;
1
[9]
Total marks …………………..[62]
Unit 1- Woodford County High School