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Cont
rol
of
Hear
t
R at
e







Heart rate needs to be altered to meet varying demands of oxygen.

Controlled by a region of the brain called the medulla oblongata.

The medulla oblongata has two centres:
1. Centre which increases heart rate = linked to sinoatrial node by sympathetic…

Page 2

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o The chemoreceptors detect the change and reduce the impulse frequency back to
normal levels.

Control by pressure receptors
o Found in the wall of the carotid arteries and the aorta.
o When blood pressure is higher than normal they send nervous impulse to the
medulla oblongata which decreases heart…

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