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Impulse of heart beat originates from : -
A
S.A. Node
B
A.V. Node
C
Vagus Nerve
D
Cardiac Nerve
Detailed Solution
The human heart is myogenic: the heartbeat starts in the heart muscle itself, not from nerves.
The sinoatrial (SA) node, in the wall of the right atrium near the opening of the superior vena cava, generates the maximum number of action potentials (70–75 per minute) and starts each heartbeat. It is called the pacemaker.
The AV node only relays the impulse to the ventricles. The vagus and cardiac (sympathetic) nerves only change the rate of the beat.
So the impulse of the heartbeat originates from the S.A. node.
The sinoatrial (SA) node, in the wall of the right atrium near the opening of the superior vena cava, generates the maximum number of action potentials (70–75 per minute) and starts each heartbeat. It is called the pacemaker.
The AV node only relays the impulse to the ventricles. The vagus and cardiac (sympathetic) nerves only change the rate of the beat.
So the impulse of the heartbeat originates from the S.A. node.