Revising the heartBill Indge

Revising the heart

In your revision, you need to:

Learn the facts

Master examination

technique

Practise the skillsL

Revising the heart

Left atrium

Left ventricle

Right atrium

Right ventricle

Learning the facts

Revising the heart

Left atrium

Left ventricle

Right atrium

Right ventricle

Revising the heart

Left atrium

Left ventricle

Right atrium

Right ventricle

Vena cava

Pulmonary artery Aorta

Pulmonary vein

Revising the heart

Left atrium

Left ventricle

Right atrium

Right ventricle

Vena cava

Pulmonary artery Aorta

Pulmonary vein

Right atrioventricular valve

Left semilunar valve

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Sinoatrial node(SAN)

Atrioventricular node (AVN)

Revising the heart

Atrioventricular node (AVN)

Sinoatrial node(SAN)

Bundle of His

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Revising the heart

Introducing tariff values

• Look through your specification for the ‘stories’ you might be expected to tell.

• Use past papers to help you to decide how many marks a question on a particular topic is likely to be worth. Add one for luck.

• Summarise the topic in the appropriate number of bullet points.

Revising the heart

• Look through your specification for the ‘stories’ you might be expected to tell.

The structure and function of the heart

Myogenic stimulation of the heart and transmission of the

subsequent wave of electrical activity

Roles of the sinoatrial node, atrioventricular node and bundle

of His

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• Use past papers to help you to decide how many marks a question on a particular topic is likely to be worth.

Explain how a heart beat is initiated and coordinated. (6 marks)

• Add one for luck 7 marks

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Controlling the heartbeat•Sinoatrial node•Myogenic and beats spontaneously•Impulse spreads over surface of atria•Atria contract, forcing blood into ventricles•Delay at atrioventricular node•Atria empty before ventricles contract•Impulse goes to base of ventricles and ventricle contracts from base upwards

• Summarise the topic in the appropriate number of bullet points.

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The table shows the pressures in the left atrium, left ventricle and aorta during a cardiac cycle.

Pressure/kPa

Stage Left atrium Left ventricle Aorta

1 0.5 0.4 10.6

2 1.2 0.7 10.6

3 0.3 6.7 10.6

4 0.4 17.3 16.0

5 0.8 8.0 12.0

Give the number of one stage where:a) blood flows into the aortab) The valve between the atrium and the ventricle is open

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Left ventricle

Aorta

Left semilunar valve

Give the number of one stagewhere blood flows into the

aorta.

For blood to flow from the left ventricle to the aorta, the pressure in the ventricle must be higher than the pressure in the aorta.

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Stage Pressure/kPa

Left atrium Left ventricle Aorta

1 0.5 0.4 10.6

2 1.2 0.7 10.6

3 0.3 6.7 10.6

4 0.4 17.3 16.0

5 0.8 8.0 12.0

Revising the heart

Left atrium

Left ventricle

Left atrioventricular valve

Give the number of one stage where the valve between the atrium and the ventricle is open.

If the valve is open, the pressure in the left atrium must be higher than the pressure in the ventricle.

Revising the heart

Stage Pressure/kPa

Left atrium Left ventricle Aorta

1 0.5 0.4 10.6

2 1.2 0.7 10.6

3 0.3 6.7 10.6

4 0.4 17.3 16.0

5 0.8 8.0 12.0

Revising the heart

Applying your knowledge

AO2 Candidates should be able to(b) apply scientific knowledge and processes to unfamiliar situations.

Remember: you may not have seen the wrapping before but you will be familiar with what is inside.

The context may be new but the biology will be familiar.

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A hole in the heart is caused when the wall between the right atrium and the left atrium does not close properly when the heart is developing. This leaves a hole through which blood can pass between the two atria.

1 Use your knowledge of pressure to explain why blood flows from the left atrium to the right atrium.

2 The blood in the right atrium of a person with a hole in the heart is different in its oxygen concentration from the blood in the right atrium of a healthy person.

(a) In what way is it different?(b) Explain what causes this difference.

3 The blood pressure in the pulmonary arteries of a person with a hole in the heart is different from that in the pulmonary arteries of a healthy person.

(a) In what way is it different?(b) Explain what causes this difference.

Revising the heart

A hole in the heart is caused when the wall between the right atrium and the left atrium does not close properly when the heart is developing. This leaves a hole through which blood can pass between the two atria.

• The material used in this question is not on your specification.

• The question will contain all the information you need so read it carefully.

• The situation may be new but the biology will be familiar. It is about the heart and blood flow.

So, don’t panic

Revising the heart

Left atriumRight atrium

Hole in the heart

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1 Use your knowledge of pressure to explain why blood flows from the left atrium to the right atrium.

(2 marks)

L R • Blood flows from high

pressure to low pressure;• Blood pressure higher in

left atrium;

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L R

(a) Has a higher oxygen concentration;

(b) Mixed with blood from left atrium

Which is coming from lungs;

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3 The blood pressure in the pulmonary arteries of a person with a hole in the heart is different from that in the pulmonary arteries of a healthy person.(a)In what way is it different?

(1 mark)(b)Explain what causes this difference. (1 mark)

L R

(a) Has a higher pressure;(b) Contains additional

blood from left atrium;

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Check with your specification and learn what you need to learn

Find some past papers and practise the skills

Graphs, tables and data handling

Applying your knowledge to new

situations