MEDICAL
HEART AND PERICARDIUM
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
initiate a sinus rhythm
|
|
|
conduct impulses to the sinoatrial node (SA node)
|
|
|
initiate ventricular depolarization
|
|
|
slow down impulses so that the atria can contract to fill the adjacent ventricles with blood
|
Detailed explanation-1: -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. The blood from the atria empties into the ventricles 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 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.