ANATOMY
LYMPHATIC SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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To allow the atria to relax, all blood from atria pumped into ventricles, hence atria will empty completely.
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To allow the ventricles to contract, pump all blood from atria into ventricles, hence atria will empty completely.
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To allow atria to contract, all blood from atria pumped into ventricles, hence atria will empty completely.
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None of the above
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Detailed explanation-1: -The delay ensures that your atria are empty of blood before the contraction stops. The atria are the heart’s upper chambers. They receive blood from your body and empty it into the ventricles.
Detailed explanation-2: -The cardiac action potential originates in the sinus node and reaches the atrioventricular node (AV node) within 100 milliseconds (ms). Slowing of conducting through the AV node delays the onset of ventricular activation with approximately 80 ms to allow optimal atrial contribution to ventricular preload.
Detailed explanation-3: -The signal travels to the AV node (atrioventricular node). This node is between the atria and the ventricles. In the AV node, the impulses are slowed down for a very short time. This allows the atria to contract a fraction of a second before the ventricles.
Detailed explanation-4: -AV node/Bundles: PR interval The AV node functions as a critical delay in the conduction system. Without this delay, the atria and ventricles would contract at the same time, and blood wouldn’t flow effectively from the atria to the ventricles. The delay in the AV node forms much of the PR segment on the ECG.