During the cardiac cycle, what is true about the left and right ventricles under normal conditions?

During the cardiac cycle, what is true about the left and right ventricles under normal conditions?

• A. They eject the same volume of blood at the same time.
• B. The left ventricle ejects more blood than the right.
• C. They eject sequentially rather than simultaneously.
• D. The right ventricle ejects more blood than the left.

Answer: (A)

In a healthy heart, the left and right ventricles act as a paired, coordinated pump and eject the same amount of blood with each heartbeat. The circulations are in series, so the volume that returns to the heart must be ejected by both ventricles over the same cardiac cycle. Although the left ventricle has to overcome higher systemic resistance, the heart adjusts so that the stroke volume—blood ejected per beat—is effectively equal on both sides. Their contraction is driven by the same electrical signal, so the ejection occurs in near synchrony within the same phase of the cycle.

In a healthy heart, the left and right ventricles act as a paired, coordinated pump and eject the same amount of blood with each heartbeat. The circulations are in series, so the volume that returns to the heart must be ejected by both ventricles over the same cardiac cycle. Although the left ventricle has to overcome higher systemic resistance, the heart adjusts so that the stroke volume—blood ejected per beat—is effectively equal on both sides. Their contraction is driven by the same electrical signal, so the ejection occurs in near synchrony within the same phase of the cycle.