1. AQA AS Physical Education PHED 1 Double Circulatory System
Physiology: Structure and function of the heart
Now we shall look at the cardiac
cycle and factors that effect the heart
rate.
By the end of this lesson you should
be able to:
• Explain the cardiac cycle in
relation to the conduction system
of the heart
• Explain the regulation and
control of the heart rate through
neural and hormonal means
The Cardiac Cycle
Task 1
Complete the following as we discuss the cardiac cycle. The Systolic phase is on the
next page.
DIASTOLE 0.5 secs
1. Both atria and ventricles are relaxed, semi-lunar valves are closed
2.
3.
4.
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2. AQA AS Physical Education PHED 1 Double Circulatory System
SYSTOLE 0.3 secs
5. Both atria contract actively forcing the remaining atrial blood into the
ventricles (atrial systole)
6.
7.
8.
9.
Notes:
___________________________________________________________________
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3. AQA AS Physical Education PHED 1 Double Circulatory System
Task 2
The list below shows the link between the cardiac cycle and the conduction system of
the heart. The stages however are muddled. In the space provided, place the list in
the correct order. Assume the first statement is in the correct place.
• Atrial diastole – both atria fill with blood
• Ventricles contract causing an increase in ventricular pressure
• AV node spreads excitation through the ventricles
• Semi-lunar valves close to prevent backflow of blood
• Ventricular diastole – ventricles fill with blood
• Semi-lunar valves are forced open. AV valves remain closed
• Rising pressure forces the AV valves to open
• Blood is forced into the aorta and pulmonary arteries
• Atrial systole – the atria force the remaining blood into the ventricles
Stage 1 Atrial diastole – both atria fill with blood
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
Stage 7
Stage 8
Stage 9
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4. AQA AS Physical Education PHED 1 Double Circulatory System
Plenary: Cardiac Cycle
The table below summarises the events of one cardiac cycle but there are some key
boxes that have been left blank. Can you complete them without using your book or
notes?
Use a second colour pen to complete the bits you do not know.
Stage of cardiac cycle Description Action of valves
atrioventricular valves are
closed
atrial diastole (relaxation) semi-lunar valves are open
rising pressure in the atria
causes the AV valves to
open and the ventricles to
fill with blood
atrioventricular valves open
semi-lunar valves are
atrial systole (contraction) closed
ventricles contract
increasing pressure in the
ventricles and forcing blood
into the aorta and
pulmonary artery
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5. AQA AS Physical Education PHED 1 Double Circulatory System
Cardiac Control Centre
Task 4
Make a poster of the CCC, make sure you have enough but not too much detail.
Task 5
Without using your book, only using your poster select the most appropriate words
from the list below to fill in the missing gaps in the paragraph on the control and
regulation of the heart.
chemoreceptors system sympathetic system
parasympathetic system SA node increases
baroreceptors decreases carbon dioxide
cardiac control centre (CCC)
At rest the ____________________ overrides the _________________and prevents
the heart rate from increasing. However once exercise begins
the_________________ increases in activity, the ______________________
decreases in activity and so heart rate is allowed to rise. Increased metabolic activity
causes an increase in the concentration of ______________ in the blood which
___________ acidity and ____________ blood pH levels. These changes are
detected by _______________________ which inform the
___________________________________ which in turn commands the
___________ to increase the rate at which it fires the cardiac impulse. Once exercise
ceases ___________________ stimulation decreases and the
_____________________once again takes over. This system responds to
information from_____________________ – the body’s in-built blood pressure
recorders.
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6. AQA AS Physical Education PHED 1 Double Circulatory System
Task 6
Again only using your poster place the factors listed below under the appropriate
headings to give a summary of the factors affecting the cardiac control centre (CCC).
Hormonal factors Neural factors Intrinsic factors
baroreceptors acetylcholine venous return temperature
noradrenaline mechanoreceptors adrenaline
chemoreceptors proprioceptors
Do you need to add anything to your poster? If so do it now.
Plenary Questions:
Now you need to work in pairs and to make up 6 questions that cover what you have
learned about the cardiac cycle and cardiac control centre:
• 2 very easy questions, worth 1 or 2 marks.
- In your exam these will usually be questions that ask you to define, state or
identify something.
- Gaining these points relies on you knowing the glossary terms.
• 2 quite difficult questions, worth 2 - 4 marks.
- In your exam these will usually be questions that ask you to describe something.
- These questions need you to have a good understanding of a topic.
• 2 harder questions, usually worth 4 - 7 marks, often having more than one part.
- These questions usually ask you to explain something.
- This needs you to be able to apply your knowledge to a specific situation.
Homework Quickie:
Make sure you have a complete glossary for Chapters.
Read back through all of the lesson sheets, PowerPoints and the
textbook and make sure all of your handouts are complete and that
you have taken detailed notes where you need them.
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