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Date May 2017 Marks available 2 Reference code 17M.3.SL.TZ1.20
Level Standard level Paper Paper 3 Time zone Time zone 1
Command term Outline Question number 20 Adapted from N/A

Question

The graph below shows a normal electrocardiogram (ECG) trace.

Using the letters provided, identify the parts of the ECG where the ventricle muscles are contracting.

[1]
a.

State what is represented by the period between the points R and R’.

[1]
b.

Outline the use of artificial pacemakers for patients with a heart condition.

[2]
c.

Markscheme

QRS/ Q to S

a.

one cardiac cycle

b.

a. artificial pacemakers deliver electrical impulses «to heart muscle» 

b. they maintain a regular heart rate / supplement the natural pacemaker 

c. they sense missing heart beats and stimulate the heart
OR
correct malfunction of SAN / sinoatrial node 

d. they coordinate contractions of atria and ventricles / left and right atria

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Option D: Human physiology » Option D: Human physiology (Core topics) » D.4 The heart
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Option D: Human physiology » Option D: Human physiology (Core topics)
Option D: Human physiology

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