3 The cardiovascular and respiratory systems
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AS PE for OCR Teacher Resource File 2nd Edition
Answers to student book tasks (part I)
TASK 1
There is no correct answer to this task. It is simply meant to ensure students can identify aerobic
and anaerobic activities and identify those which are a mixture of the two. Be careful not to jump
too heavily into A2 work topics during these discussions as this may confuse students.
1. It is advisable to choose extreme examples:
Aerobic = marathon
Anaerobic = 100m sprint
Mix = team games
You can then challenge them further as to the % mix, more aerobic or anaerobic.
Basketball / Volleyball = more anaerobic high intensity work.
Football / Hockey = more an equal mix
2. Question 2 takes it further in terms of positional differences within different activities.
GK in all team games are predominantly anaerobic. Midfield positions / centre in netball are
generally more aerobic. Forwards are generally more anaerobic.
You could consider how skill/physical attributes can negate the above generalizations, e.g. old
fashioned centre forwards are not generally high intensity sprinters.
The comparison exercise looks to identify any similarities between different activities and
individual positions within these activities.
TASK 2
1. The heart is the first tissue/organ to receive oxygenated blood. Coronary arteries lead directly
from the aorta and immediately supply oxygen to the myocardium wall of the heart. Having just
returned from the lungs, coronary artery blood is fully loaded with oxygen.
2. Having a constant supply of O2, the heart works aerobically. It never fatigues, until you die of
course, hence it is made up of slow twitch type I fibres. As quickly as it may produce waste
products, e.g. lactic acid, it immediately removes them, preventing any fatigue.
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3 The cardiovascular and respiratory systems
AS PE for OCR Teacher Resource File 2nd Edition
TASK 3
This task is best answered as a table:
Structure
Vena cavae
Right atrium
Tricuspid valve
Right ventricle
Pulmonary valve
Pulmonary artery
Alveoli/lung
capillaries
Pulmonary veins
Left atrium
Bicuspid valve
Left ventricle
Aortic valve
Aorta
What you are carrying
Deoxygenated blood
Oxygenated blood
TASK 4
1. Sketch should look something like the heart in the centre of Figure 3.1.2 with the chambers
labelled correctly.
2. Insert Figure 3.1.4 from page 64 of student book – diagram of showing the structures involved
in the conduction of the cardiac impulse.
3. This information can be found on pages 63 and 64 of the student book.
TASK 5
Diagram from task 4 in old TRF
TASK 6
72 bpm x 70ml = 5040ml or Dm3 or 5.04 L or Dm3
This third volume is cardiac output, ‘the volume of blood ejected from one/both heart ventricles in
one minute’. Students should be able to come close to a definition using the definition of Stroke
Volume.
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3 The cardiovascular and respiratory systems
AS PE for OCR Teacher Resource File 2nd Edition
TASK 7
5000
= 83.3ml
60
This question is challenging students to understand the relationship between Q, SV and HR and
summarize what determines SV and therefore what needs to change for SV to increase. A more
detailed and expanded explanation is looked at in Task 8.
SV is the volume of blood pumped out during each heart beat. SV is dependent upon the capacity of
the heart to fill and empty. If SV is to increase, both filling (EDV) and emptying (force of
ventricular contraction) must increase.
TASK 8
This question attempts to build upon Task 7 while applying the knowledge to both rest and
exercising conditions.
Stroke volume increases in the trained athlete primarily due to hypertrophy, an increase in the
size/thickness of the heart myocardium. Hypertrophy of the heart myocardium is a long-term
adaptation to aerobic training. This is evident in the table. The trained athlete’s HR of 50, is known
as ‘bradycardia’. Hypertrophy increases the heart’s capacity to fill (EDV), which increases the
stretch/recoil from the ventricle walls, thus increasing the force of contraction and allowing it to
empty more (SV). If more blood is pumped out per each beat (SV) then the heart of a trained athlete
does not have to beat as many times to maintain the same cardiac output as an untrained athlete,
hence HR decreases.
TASK 9
1. a) The actual physical size of the heart chambers and time for filling limits its capacity to fill
and this determines the volume of blood it can ultimately eject/empty.
b) With SV reaching maximal values during sub maximal work any further increase in work
requiring a greater cardiac output can only come from an increase in HR. As HR increases, the
time for the heart to fill (diastole) decreases further.
2. This question attempts to recap on the language used to explain changes in SV during rest and
exercise conditions, but asks the student to apply this knowledge to improve performance.
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3 The cardiovascular and respiratory systems
AS PE for OCR Teacher Resource File 2nd Edition
Table to show/describe changes in EDV, ESV and SV during rest and exercise:
Changes
EDV
ESV
SV
Rest (ml)
130
60
120
During exercise (ml)
130
10
70
Benefits to improve performance:

Increase in SV during exercise increases cardiac output/blood ejected per minute.

Increase transport/supply of blood/O2 to working muscles.

Therefore there is less anaerobic work at the start of the exercise.

This reduces OBLA/anaerobic work at the start of the exercise.

This delays/prevents the onset of muscle fatigue.

This speeds up the recovery process after exercise.
TASK 10
This task makes students re-visit HR responses to exercise and highlights the main differences (in bold)
between sub-maximal and maximal exercise.
Sub-maximal exercise
E.g.
A,B,E,F,G,
Maximal exercise
Eg.
A,B,C,F,G,H
TAKE IT FURTHER
The ‘cardiovascular drift’ is the gradual decrease in SV and increase in HR during prolonged
exercise. Research and discuss what might cause the cardiovascular drift.
Answer

CV drift is the gradual decrease in SV and increase in HR during prolonged exercise.

Arterial (Systemic / Pulmonary) pressure also decline.
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3 The cardiovascular and respiratory systems
AS PE for OCR Teacher Resource File 2nd Edition
This affect is generally associated with an increase in body temperature which causes an increase in
Q redirected to the skin to reduce body temperature and decrease in blood plasma volume as a result
of sweating. Together, these decrease VR which in turn decreases EDV which in turn decreases SV.
The HR increases to compensate for the decrease in SV to maintain the required Q.
TASK 11
1 to 3 are tasks to complete with no answers.
4. HR should increase from supine to exercising conditions.
HR will increase to compensate for the decrease in SV from supine to sitting and standing in an
attempt to maintain Q.
HR continues to increase with exercise intensity, to increase Q, to meet the increasing demands
for O2 from the active muscles. HR must continue to increase as SV reaches maximal values
during sub-maximal work and any further increase in Q is a result of an increase in HR.
5. This question raises the issues concerning differences in HR and may be pursued along the
following lines:
1 Gender – Generally males have lower resting and higher maximal HR.
2 Fitness level – The more aerobically athletic the individual the lower the resting HR and
higher maximal HR.
3 Activity/sports – Comparison of aerobic versus anaerobic activities/sports. The more
aerobic the activity then generally the lower the resting and maximal HR.
TASK 12
1. Heart rate increases in line with exercise intensity.
2. SV decreases from supine to sitting, and decreases further to standing. Blood pooling does not
occur in the supine position so VR is easily returned to the heart. In sitting and standing VR has
to return against gravity, increasing blood pooling which reduces VR and therefore SV
(Starlings Law).
3. Cardiac output is a product of SV and therefore decreases in line with SV from supine to sitting
and standing.
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3 The cardiovascular and respiratory systems
AS PE for OCR Teacher Resource File 2nd Edition
TAKE IT FURTHER
1. Swimmer is in a supine/flat position so there will be less blood pooling in legs allowing an
increase in venous return.
2. Cycling position causes more blood pooling and using less active muscles reduces the muscle
pump action which helps VR.
TASK 13
This question requires students to apply the description and explanation of the response of HR to both
sub-maximal and maximal exercise.
Depending upon the results, and therefore graphs produced, the answers will obviously differ.
Some issues to consider include:

Validity refers to the appropriateness of the investigation to measure HR. Does the investigation
measure what it purports to measure? In this respect it is a valid test?

Reliability refers to the consistency of the results. Can the test be repeated and similar results
obtained?
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