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Year 10
AQA

The cardiac cycle

I can describe the mechanics of a heartbeat.

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New
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Year 10
AQA

The cardiac cycle

I can describe the mechanics of a heartbeat.

Download all resources
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Share activities with pupils
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Lesson details

Key learning points

  1. The cardiac cycle consists of two main phases: diastole and systole.
  2. Diastole is the phase when the heart chambers relax and fill with blood.
  3. Systole is the phase when the heart chambers contract and pump blood out at high pressure.
  4. The septum divides the left and right sides of the heart to prevent oxygenated blood mixing with deoxygenated blood.

Keywords

  • Cardiac cycle - the sequence of events in a heartbeat, including contraction and relaxation phases

  • Systole - when the heart is contracting causing ejection of blood

  • Diastole - when the heart is relaxing and filling with blood

Common misconception

The ba-dum of the heart beat represents the left then right side contracting.

The heart relaxes (diastole) to fill with blood then first phase of contraction squeezes blood from the top two atria down into the ventricles before the valves close off and then the second phase of contraction squeezes blood out of the ventricles.

A nice way to practically represent this is to get each pupil to write a different part of the cardiovascular system (e.g. left atrium) on a mini whiteboard and then add a description of the function of that part and line up in order of how blood passes through the different chambers.
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Teacher tip
equipment-required

Equipment

Play dough or clay from the art department is perfect for a bit of hands on modelling of a heart in task B or this could be replaced with an extended answer exam style question.

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Licence

This content is © Oak National Academy Limited (2025), licensed on

Open Government Licence version 3.0
except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Starter quiz

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6 Questions

Q1.
Which chamber does blood first enter the heart into from the lungs?
right atrium
right ventricle
Correct answer: left atrium
left ventricle
aorta
Q2.
Which of the following blood vessels carries blood at low pressure?
arteries
Correct answer: veins
capillaries
Q3.
Blood is pumped out of the right atrium into the right before being pumped out of the heart.
Correct Answer: ventricle, ventracle
Q4.
Which of the following statements are correct?
The atria are the biggest chambers in the heart.
The ventricles are at the top of the heart.
Correct answer: The septum prevents oxygenated blood from mixing with deoxygenated blood.
The aorta take blood to the lungs.
Q5.
The tricuspid valve separates the atrium and ventricle.
Correct Answer: right
Q6.
Place the following parts of the circulatory system in the correct order for blood flow starting at the lungs.
1 - pulmonary vein
2 - left atrium
3 - left ventricle
4 - aorta
5 - muscles
6 - vena cava
7 - right atrium

Exit quiz

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6 Questions

Q1.
Why does the heart make a ba-dum sound?
to coordinate with the lungs
Correct answer: contraction of atria then ventricles with a short pause in between
contraction of ventricles then atria with a short pause in between
It represents the relaxation phase of the heartbeat.
Q2.
Which of the following does systole refer to?
atria relaxing
ventricles relaxing
Correct answer: the contraction phase
blood filling up in the heart
Q3.
Which of the following is the best description of the cardiac cycle?
the circulation of blood to the lungs
the circulation of blood to the body
the circulation of blood to the brain
Correct answer: the sequence of events in a heartbeat, including contraction and relaxation
the division of left and right sides of the heart
Q4.
The relaxation phase of the cardiac cycle is known as ...
Correct Answer: diastole, dyastole
Q5.
Match the following key terms and descriptions.
Correct Answer:cardiac cycle,the sequence of events in a heartbeat (contraction and relaxation)
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the sequence of events in a heartbeat (contraction and relaxation)

Correct Answer:systole,the contraction phase where blood is ejected from the heart
tick

the contraction phase where blood is ejected from the heart

Correct Answer:diastole,the relaxation phase where the heart fills with blood
tick

the relaxation phase where the heart fills with blood

Q6.
Place the following stages of the cardiac cycle in the correct order, starting with the heart filling with blood.
1 - The heart relaxes (called diastole) and fills with blood returning via the veins
2 - The heart contracts (called systole) from the top chambers (atria) first.
3 - The tricuspid and bicuspid valves open to allow blood down.
4 - The tricuspid and bicuspid valves close to prevent backflow.
5 - The ventricles contract ejecting blood from the heart into the arteries.
6 - The next cycle begins with diastole (relaxation).