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Multiple Choice
What structure primarily controls the heartbeat in the human body?
A
Sinoatrial (SA) node
B
Purkinje fibers
C
Bundle of His
D
Atrioventricular (AV) node
Verified step by step guidance
1
Understand that the heartbeat is controlled by the cardiac conduction system, which is responsible for generating and conducting electrical impulses throughout the heart.
Identify the key components of the cardiac conduction system: the Sinoatrial (SA) node, Atrioventricular (AV) node, Bundle of His, and Purkinje fibers.
Recognize that the Sinoatrial (SA) node is known as the natural pacemaker of the heart because it initiates the electrical impulses that set the rhythm for the heartbeat.
Note that the electrical impulse generated by the SA node travels through the atria, causing them to contract, and then reaches the Atrioventricular (AV) node.
Understand that while the SA node primarily controls the heartbeat, the AV node, Bundle of His, and Purkinje fibers play roles in conducting the impulse through the heart to ensure coordinated contraction.