AWhat is happening during the pause phase when the heart is

A.What is happening during the “pause” phase when the heart is resting (relaxing)?

1.Ventricles are contracting.

2.Atria are contracting

3.Ventricles are filling

B.What causes the abnormal swishing or whooshing sound that is heard as blood regurgitates back into an atrium from its associated ventricle?

1.pulmonary trunk expansion

2. blood turbulence

3.semilunar valve closure

4.aortic recoil

Solution

During the pause phase 3. ventricles are filling

The pause phase is critical to heart function as it allows the atrial cardiomyocytes to complete their contraction by pumping blood into the ventricles even before the impulse is transmitted to the cells of the ventricles. During pause the AV atrioventricular node depolarizes and transmits the impulse to the AV bundle. It takes the impulse approximately 100 ms to pass through the node. This delay in transmission is attributable to the small diameter of the cells of the node.