Impulse for contraction starts in the SA node. From there it travels to the AV node. It is then conducted to the Purkinje fibres through the Bundle of His fibres. The Purkinje fibre situated in the lateral walls of the ventricles spread the impulse to the ventricles. Thus the ventricular contraction is initiated. The pressure exerted by the blood pushed into the aortic arteries is recorded as pulse.

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