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Question 18N.3.SL.TZ0.17b

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Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.3.SL.TZ0.17b
Level SL Paper 3 Time zone TZ0
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 2]
18N.3.SL.TZ0.17b

An electrocardiogram (ECG) records the electrical activity of the heart over a period of time using electrodes placed on the skin. The ECG shown is from a patient whose heart was beating irregularly until it was treated using a defibrillator (arrows) which restored normal electrical activity.

(b)

Outline how a defibrillator is used to restore normal heartbeat.

[2]

Markscheme

a. «paddles/electrodes/defibrillator» deliver an electric shock to the heart ✔

b. depolarizes cardiac muscle ✔

c. enables the pacemaker/SA node to regain control ✔

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