What occurs during the atrial and ventricular filling phase?

What occurs during the atrial and ventricular filling phase?

• A. Blood passively flows into the ventricles, and AV valves remain open.
• B. The ventricles actively eject blood into the arteries.
• C. The SL valves are pushed open.
• D. AV valves close at the start of systole.

Answer: (A)

During this phase the heart is in diastole and the ventricles are relaxing. Blood flows passively from the atria into the ventricles because atrial pressure is higher than ventricular pressure while the atrioventricular (AV) valves are open. This is the main filling flow. The semilunar valves stay closed, so there’s no ejection into the arteries yet. Atrial contraction toward the end of this phase (the atrial kick) adds a final amount of blood into the ventricles, but the majority of filling is passive.

During this phase the heart is in diastole and the ventricles are relaxing. Blood flows passively from the atria into the ventricles because atrial pressure is higher than ventricular pressure while the atrioventricular (AV) valves are open. This is the main filling flow. The semilunar valves stay closed, so there’s no ejection into the arteries yet. Atrial contraction toward the end of this phase (the atrial kick) adds a final amount of blood into the ventricles, but the majority of filling is passive.