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Multiple Choice
What structure establishes the rhythm and rate of the heartbeat?
A
Bundle of His
B
Atrioventricular (AV) node
C
Purkinje fibers
D
Sinoatrial (SA) node
Verified step by step guidance
1
Understand that the heart's rhythm and rate are controlled by the cardiac conduction system, which is responsible for generating and conducting electrical impulses.
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 heart's natural pacemaker because it initiates the electrical impulses that set the rhythm and rate of the heartbeat.
Note that the SA node is located in the right atrium of the heart and generates electrical impulses that cause the atria to contract, pushing blood into the ventricles.
Understand that while other structures like the AV node, Bundle of His, and Purkinje fibers play roles in conducting impulses, the SA node is primarily responsible for establishing the heart's rhythm and rate.