During the ejection period, what occurs?

During the ejection period, what occurs?

• A. Blood is pumped into the aorta and the pulmonary trunk.
• B. The ventricles fill with blood from the atria.
• C. The atrioventricular valves open to allow atrial filling.
• D. The heart rate decreases.

Answer: (A)

The main concept is what happens during ventricular ejection in the cardiac cycle. During ejection, the ventricles contract (systole) and pressure inside them rises above the pressures in the aorta and pulmonary trunk. This causes the semilunar valves to open, so blood is actively pumped from the ventricles into the aorta and pulmonary trunk, supplying the systemic and pulmonary circulations. This is why the best answer is that blood is pumped into the aorta and the pulmonary trunk. The other events described don’t occur during this phase: ventricular filling from the atria happens during diastole, the atrioventricular valves are closed to prevent backflow during ejection, and the heart rate changing is not the defining feature of the ejection period.

The main concept is what happens during ventricular ejection in the cardiac cycle. During ejection, the ventricles contract (systole) and pressure inside them rises above the pressures in the aorta and pulmonary trunk. This causes the semilunar valves to open, so blood is actively pumped from the ventricles into the aorta and pulmonary trunk, supplying the systemic and pulmonary circulations.

This is why the best answer is that blood is pumped into the aorta and the pulmonary trunk. The other events described don’t occur during this phase: ventricular filling from the atria happens during diastole, the atrioventricular valves are closed to prevent backflow during ejection, and the heart rate changing is not the defining feature of the ejection period.