Which component of the electrical conduction system of the heart is most responsible for the synchronized contraction of cardiac muscle tissue?

• A. Bundle of His
• B. Sinoatrial (SA) node
• C. Purkinje fibers
• D. Atrioventricular (AV) node

Answer: (B)

Verified step by step guidance

1. Begin by understanding the role of the electrical conduction system in the heart, which is responsible for initiating and coordinating the contraction of cardiac muscle tissue.
2. Identify the key components of the heart's conduction system: the Sinoatrial (SA) node, Atrioventricular (AV) node, Bundle of His, and Purkinje fibers.
3. Recognize that the Sinoatrial (SA) node is known as the heart's natural pacemaker. It initiates the electrical impulse that triggers the heartbeat, setting the rhythm for the entire heart.
4. Understand that the SA node's impulse causes the atria to contract, and this impulse is then transmitted to the Atrioventricular (AV) node, which acts as a gatekeeper, delaying the impulse before it passes to the ventricles.
5. Learn that the synchronized contraction of cardiac muscle tissue is primarily initiated by the SA node, as it sets the pace and rhythm for the heart, ensuring that the atria contract first, followed by the ventricles.