PATHOLOGY MCQ
HEART
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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initiate a sinus rhythm
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conduct impulses to the sinoatrial node (SA node)
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initiate ventricular depolarization
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slow down impulses so that the atria can contract to fill the adjacent ventricles with blood
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Detailed explanation-1: -The atrioventricular node delays impulses by approximately 0.09s. This delay in the cardiac pulse is extremely important: It ensures that the atria have ejected their blood into the ventricles first before the ventricles contract.
Detailed explanation-2: -The AV node is a highly specialized conducting tissue (cardiac, not neural) that slows the impulse conduction considerably (to about 0.05 m/sec), which allows for sufficient time to complete atrial depolarization and contraction prior to ventricular depolarization and contraction.
Detailed explanation-3: -The atrioventricular node is the second of several components of the cardiac conduction system. This intrinsic conduction system is responsible for generating impulses for the contractions of the heart and ensuring coordinated blood flow through the chambers of the heart.