Unit 1 – The Heart – Past Paper
Q1. Table 1 shows the blood pressure in the left atrium, the left ventricle and the aorta at different
stages in a cardiac cycle. These three parts of the circulatory system have been labelled A, B
and C.
Blood pressure/kPa
Time/s
Part A
(left atrium)
Part B
(left ventricle)
Part C
(aorta)
0
0.6
0.3
12.1
0.1
1.1
0.7
11.7
0.2
0.6
12.6
11.8
0.3
0.9
14.8
13.6
0.4
1.2
1.1
12.8
0.5
0.6
0.2
12.6
0.6
0.6
0.2
12.4
Table 1
(a)
What is the evidence from the figures in Table 1 that part B is the ventricle?
.....................................................................................................................................
..................................................................................................................................... (1)
(b)
(i)
At 0.3 s, the atrioventricular valves are closed. Give the evidence from Table 1
which supports this statement.
..........................................................................................................................
..........................................................................................................................
(ii)
For approximately how long is the valve between the left ventricle and the aorta
open? Give the reason for your answer.
..........................................................................................................................
..........................................................................................................................
.......................................................................................................................... (2)
(1)
(c)
The figures in the third column of Table 1 show the changes in pressure in the left
ventricle.
(i)
Describe how the pressure in the left ventricle differs from that in the right
ventricle.
.......................................................................................................................... (1)
(ii) Explain what causes this difference.
..........................................................................................................................
.......................................................................................................................... (1)
Table 2 compares some features of different blood vessels from a dog.
Cranford Community College
1
Property
Artery
Arteriole
Capillary
Diameter of lumen
0.4
30 m
8 m
Thickness of wall
1 mm
20 m
1 m
Tissues present in wall
Endothelium
×
×
Elastic tissue
Muscle
Tissue present
Tissue absent
What is the thickness of one of the endothelial cells lining these blood vessels?
Table 2
(d)
Key
×
Answer: ............................................................... µm (1)
(e)
Explain why an arteriole may be described as an organ.
.....................................................................................................................................
.....................................................................................................................................
.................................................................................................................................... (2)
(f)
Use the information in Table 2 to explain how the structure of the walls of arteries,
arterioles and capillaries is related to their function.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(6)
(Total 15 marks)
Q2.
(a)
Explain why a vein is described as an organ.
.....................................................................................................................................
..................................................................................................................................... (1)
(b)
The diagram shows a vein passing between two muscles.
Cranford Community College
2
Valve A
Muscle
Valve B
Vein
(c)
(i)
When the muscles contract, the pressure of the blood in the part of the vein
between valves A and B changes. Explain how this change in pressure, together
with the action of the valves, helps the blood to flow to the heart
...........................................................................................................................
...........................................................................................................................
.......................................................................................................................... (3)
(ii)
Suggest how blood is returned to the heart when the muscles are not contracting
...........................................................................................................................
........................................................................................................................... (1)
The graph shows the relationship between the pressure in the veins returning blood into
the heart and stroke volume.
120
100
80
Stroke
volume/ 60
cm 3
40
20
0
0
1
2
3
5
6
4
Pressure in veins/kPa
7
8
9
(i)
Describe the relationship between stroke volume and pressure in the veins.
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (1)
(ii)
What information would you need, other than that in the graph, to calculate this
person’s cardiac output
........................................................................................................................... (1)
(Total 7 marks)
Cranford Community College
3
Q3.
The table shows some information about blood vessels in a dog.
Blood vessels
Mean
diameter/cm
Total
number
0.1
0.002
0.0008
0.24
600
4  107
1.2  109
600
Main arteries
Arterioles
Capillaries
Main veins
Other blood
vessels
(a)
(b)
Mean
length/cm
10.0
0.2
0.1
10.0
Total
cross-sectional
area/cm2
5
125
600
27
Total volume/
cm3
50
25
60
270
525
Use your knowledge of the pattern of blood circulation in a mammal to explain why
(i)
the total number of arterioles is more than the total number of main arteries;
...........................................................................................................................
........................................................................................................................... (1)
(ii)
the total number of main arteries is the same as the total number of main veins.
...........................................................................................................................
........................................................................................................................... (1)
(i)
Explain how the total volume of blood in the arterioles was calculated.
...........................................................................................................................
........................................................................................................................... (1)
(ii)
Calculate the percentage of blood in the blood vessels which is in the capillaries.
Show your working.
Answer ....................................... %
(i)
Name one tissue or organ in which the volume of blood in the capillaries increases
during exercise.
........................................................................................................................... (1)
(ii)
Describe the part played by the arteriole walls in reducing blood flow to the
capillaries in the intestines during exercise.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (3)
(2)
(c)
(Total 9 marks)
Q4.
The diagram shows a section through a human heart.
C
B
A
D
Cranford Community College
4
(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)
(b)
is a vein which contains oxygenated blood?
........................................................................................................................... (1)
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
Y
Time
Z
(c)
Describe what the graphs show about the pressure and volume in the ventricle between
times X and Y.
.....................................................................................................................................
..................................................................................................................................... (1)
(d)
At point Y, the valve between the aorta and the ventricle opens. Use the information
about pressure on the graph to explain why.
.....................................................................................................................................
..................................................................................................................................... (1)
(e)
Explain the changes in the volume of the ventricle between times X and Z.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Cranford Community College
5
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 9 marks)
Q5.
(a)
Describe the route taken by a red blood cell from leaving the right ventricle of the heart to
entering the left atrium.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(b)
The drawing shows a red blood cell.
X
Y
Y
(i)
X
The centre of this cell appears light in colour when seen with an optical
microscope. Explain why.
.....................................................................................................................................
.....................................................................................................................................
1
(ii) Draw diagrams in the space below to show the appearance of this cell along
Section X-X
Section Y-Y
(2)
(c)
There are no nuclei or other cell organelles in the cytoplasm of red blood cells.
Describe one way in which the structure of a red blood cell
(i)
is similar to the structure of a lymphocyte;
.....................................................................................................................................
................................................................................................................................ (1)
(ii)
is different from the structure of a prokaryotic cell such as a bacterium.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 7 marks)
Q6.
The diagram shows the heart and the tissues which control the heart beat. The figures on the
diagram show the time in seconds taken for a wave of electrical activity to spread from the
sinoatrial node.
Cranford Community College
6
A
0.01 seconds
B
0.04 seconds
C
0.16 seconds
D
0.17 seconds
(a)
(i)
The diagram shows that the valve between the right atrium and the right ventricle is
closed. What does this indicate about the relative pressures in the right atrium and
the right ventricle?
.....................................................................................................................................
.....................................................................................................................................
................................................................................................................................ (1)
(ii)
Complete the diagram to show whether the valve between the left atrium and the
left ventricle is open or closed.
(1)
(b)
The rate at which the electrical activity passes from B to C is important in controlling the
heart beat. Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(c)
The heart rate of a sleeping person is low. Explain how nerves supplying the heart may
produce a low heart rate in a sleeping person.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (3)
(Total 7 marks)
Q7.
The diagram shows a section through the wall of the aorta.
Cranford Community College
7
Inner layer of epithelial cells
Middle layer containing elastic
fibres and smooth muscle
Outer layer containing collagen
Blood vessels in wall of aorta
(a)
Explain why the aorta is an organ.
.....................................................................................................................................
.................................................................................................................................... (1)
(b)
Explain how cells in the outer layer of the wall of the aorta get oxygen for respiration.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(c)
(i)
The wall of the aorta helps to smooth out blood pressure in the aorta. Explain how.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
................................................................................................................................ (2)
(ii)
The changes in the pressure of blood in the aorta can be measured. Explain why
this information would enable you to measure the heart rate.
.....................................................................................................................................
................................................................................................................................ (1)
(Total 6 marks)
Q8.
The pressure of the blood in an artery was measured during a cardiac cycle. The minimum
pressure was 9.6 kPa and the maximum pressure was 13.4 kPa.
(a)
Describe how the increase in pressure of the blood in the artery results from the events in
the cardiac cycle.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(b)
The elastin fibres in the wall of the artery help to smooth out the flow of blood. What
happens to these fibres as the pressure of the blood in the artery changes?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................2)
Give one way in which the structure of the wall of an artery is similar to the structure of
the wall of a capillary.
.....................................................................................................................................
(c)
Cranford Community College
8
.....................................................................................................................................
(1)
(Total 5 marks)
Q9.
(a)
Explain why both the heart and arteries are described as organs.
.....................................................................................................................................
.....................................................................................................................................1)
The table shows changes in the volume of blood in the left ventricle over a period of one second.
Time / s
Volume of blood as
percentage of maximum
0
70
0.1
100
0.2
70
0.3
30
0.4
0
0.5
35
0.6
60
0.7
70
0.8
70
0.9
100
1.0
70
Use information in the table to answer the following questions.
(b)
What is the approximate length of one cardiac cycle?
..................................................................................................................................... (1)
(c)
At what time is there least blood in the right ventricle? Explain your answer.
.....................................................................................................................................
..................................................................................................................................... (1)
(d)
(i)
Between which times are the muscles in the wall of the left atrium contracting?
Give the reason for your answer.
Times..........................................................................................................................
Reason........................................................................................................................
............................................................................................................................... (1)
(ii)
Between which times are the semi lunar valves in the arteries open? Give the
reason for your answer.
Times..........................................................................................................................
Reason........................................................................................................................
(1)
(e)
The maximum volume of blood in the left ventricle is 45 cm3. Calculate the volume of
blood in the left ventricle at 0.5 s. Show your working.
Volume of blood = ................................................. cm3
(2)
(Total 7 marks)
Q10. The graph shows changes in the volume of blood in the left ventricle.
Cranford Community College
9
140
120
100
Volume /
cm 3
80
60
40
20
0
0
0.2
0.4
0.6
0.8
1.0
Time / s
(a)
(b)
Between which times is the left atrium contracting? Give the evidence from the graph
that supports your answer.
Times..........................................................................................................................
Evidence …….............................................................................................................
............………............................................................................................................. (2)
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
Skeletal muscles
Kidney
Brain
Heart muscle
Rate of blood flow / cm3 minute–1
at rest
during exercise
1 000
16 000
1 200
1 200
750
300
1 200
(d)
Suggest a value for the rate of blood flow to the brain during exercise.
............………..............................................................................................................
(e)
(i)
(1)
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.............................................
Cranford Community College
10
(1)
(ii)
3
–1
At rest the rate of flow of blood to the heart muscle is 0.9 cm g per minute.
Calculate the volume of blood 1g of heart muscle would receive in 5 minutes of
vigorous exercise.
Answer.............................................
(1)
(Total 9 marks)
11.
(a)
(b)
(i)
Explain the meaning of the term atheroma.
...........................................................................................................................
........................................................................................................................... (1)
(ii)
Explain why atheroma may lead to a blood clot.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................2
The diagram shows an external view of the heart. The position of a blood clot is marked.
(i)
On the diagram, shade the area of the heart muscle which is likely to die as a result
of the blood clot.
(ii)
Explain why this area of the heart muscle is likely to die.
...........................................................................................................................
........................................................................................................................... (1)
(1)
(c)
High blood pressure is a risk factor associated with damage to the circulatory system.
Suggest two ways in which prolonged high blood pressure may affect the arteries.
1 ............……….......................................................................................................…
............………..............................................................................................................
2 ............……….....................................…..................................................................
............………..............................................................................................................
(2)
(Total 7 marks)
Q12. This diagram shows a human heart seen from the front.
Cranford Community College
11
B C
D
A
X
Y
(a)
(i)
Which one or more of vessels A to D contains oxygenated blood?
........................................................................................................................... (1)
(ii)
During a cardiac cycle, the pressure of the blood in vessel C is higher than the
pressure of the blood in vessel B. Explain what causes this difference in pressure.
...........................................................................................................................
........................................................................................................................... (1)
(b)
What does the diagram suggest about the pressure in the atria compared to the pressure in
the ventricles at the stage in the cardiac cycle represented in the diagram? Explain your
answer.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(c)
The wave of electrical activity which coordinates the heart beat is delayed slightly at part
X. It then passes along part Y to the base of the ventricles.
Explain the importance of
(i)
the slight delay at part X;
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (2)
(ii)
the electrical activity being passed to the base of the ventricles.
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (2)
(Total 8 marks)
Q13. The table shows the relative thickness of layers in the walls of an artery and a vein.
Thickness / µm
Layer in wall
Endothelium
Smooth muscle
Elastic tissue
Connective tissue
Artery
20
490
370
120
Vein
20
240
240
120
(a)
Explain why a vein may be described as an organ.
.....................................................................................................................................
..................................................................................................................................... (1)
(b)
(i)
Use information from the table to suggest the thickness of a capillary wall.
Give the reason for your answer.
Cranford Community College
12
........................................................................................................................... (1)
(ii)
The diameter of the artery was 4 mm. Calculate the diameter of the lumen of this
artery. Show your working.
Answer................................. (2)
(c)
Explain how the elastic tissue in the wall helps to even out the pressure of blood flowing
through the artery.
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
Q14. The diagram shows a section through a human heart.
Y
B
A
X
C
D
(a)
Complete the table to show whether the valves are open or closed when the pressure in
chamber C is at its highest.
Location of valve
Valve open or closed
between chamber C and chamber B
between chamber D and chamber A
between chamber C and blood vessel Y
(b)
Explain the advantage of having:
(i)
a large amount of elastic tissue in blood vessel Y;
...........................................................................................................................
...........................................................................................................................
.......................................................................................................................... (2)
(ii) valves in blood vessels such as blood vessel X.
...........................................................................................................................
........................................................................................................................... (1)
(2)
(Total 5 marks)
Q15. The diagram shows a human heart
(a)
On the diagram, label the position of the atrioventricular node.
(1)
Cranford Community College
13
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
(b)
(c)
S
0.1
0.2
0.3
0.4
Time/seconds
0.5
0.6
0.7
0.8
(i)
The QRS wave is associated with the spread of electrical activity over the ventricle.
Explain the evidence in the graph which supports this.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
.......................................................................................................................... (2)
(ii)
Explain why there is no change in the electrical activity between 0.31s and 0.77s.
...........................................................................................................................
........................................................................................................................... (1)
(i)
At what time in the cardiac cycle does the aortic semi lunar valve open?
........................................................................................................................... (1)
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.
(ii)
(2)
(Total 7 marks)
Q16. The graph shows the heart rate before, during and after exercise.
160
Heart rate/
beats per
120
minute
80
0
0
5
Rest
Cranford Community College
10
15
Time/minutes
Exercise
20
25
Recovery
14
(a)
Explain how the nerves connected to the heart cause the changes seen during
(i)
the first 2 minutes of exercise;
..........................................................................................................................
..........................................................................................................................
(ii) the recovery period.
..........................................................................................................................
.......................................................................................................................... (4)
(b)
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
(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 =..........................
(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?
..........................................................................................................................
..........................................................................................................................
(2)
(1)
(Total 7 marks)
Q17. (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
0.4
0.6
Time/seconds
0.8
1.0
(i)
Use the graph to calculate the heart rate in beats per minute. Show your working.
Answer..............................
(ii)
The atrioventricular valve closes at 0.1 seconds.
Explain the evidence from the graph which supports this statement.
(2)
Cranford Community College
15
..........................................................................................................................
.......................................................................................................................... (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.
.....................................................................................................................................
.....................................................................................................................................(1)
(Total 4 marks)
Q18. 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.
(i)
Describe how the regular contraction of the atria and ventricles is initiated and
coordinated by the heart itself.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (5)
(ii)
Describe the role of the nervous system in modifying the heart rate in response to an
increase in blood pressure.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (5)
(Total 10 marks)
Q19. 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.
Time / s
0.0
0.1
0.2
0.3
0.4
Left atrium
0.5
1.2
0.3
0.4
0.8
Blood pressure / kPa
Left ventricle
0.4
0.7
6.7
17.3
8.0
Aorta
10.6
10.6
10.6
16.0
12.0
(i)
At which time is blood flowing into the aorta?
......................................................................................................................….(1)
(ii)
Between which times are the atrioventricular valves closed?
Cranford Community College
16
(b)
(c)
......................................................................................................................….(1)
The maximum pressure in the left ventricle is higher than the maximum pressure in the
right ventricle. What causes this difference in pressure?
.....................................................................................................................................
..................................................................................................................................... (1)
The information below compares some features of different blood vessels.
Blood vessel
Property
Mean diameter
of vessel
Mean
thickness of
wall
Artery
Capillary
Vein
4.0 mm
8.0 m
5.0 mm
1.0 mm
0.5 m
0.5 mm
Relative thickness (shown by length of bar)
Tissues
present in
wall
Endothelium
Elastic tissue
Muscle
Use the information to explain how the structures of the walls of arteries, veins and capillaries
are related to their functions.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (6)
(Total 9 marks)
Cranford Community College
17