The function of systole is to:

The function of systole is to:

• A. Relax ventricles
• B. Eject blood into the arteries
• C. Fill the atria
• D. Decrease peripheral resistance

Answer: (B)

Systole is the contraction phase of the heart, during which the ventricles pump blood outward into the arteries. As the ventricles contract, pressure rises, the atrioventricular valves close, and the semilunar valves open, allowing blood to be ejected into the aorta and pulmonary artery. This is the core action of systole—driving blood into the systemic and pulmonary circulations. Relaxing ventricles, by contrast, is diastole, the phase when the heart fills with blood. Filling the atria occurs mainly before or during ventricular diastole, not during systole. Decreasing peripheral resistance isn’t a direct function of the heart’s pumping action in the moment of systole; it’s regulated mainly by the tone of the peripheral vessels.

Systole is the contraction phase of the heart, during which the ventricles pump blood outward into the arteries. As the ventricles contract, pressure rises, the atrioventricular valves close, and the semilunar valves open, allowing blood to be ejected into the aorta and pulmonary artery. This is the core action of systole—driving blood into the systemic and pulmonary circulations.

Relaxing ventricles, by contrast, is diastole, the phase when the heart fills with blood. Filling the atria occurs mainly before or during ventricular diastole, not during systole. Decreasing peripheral resistance isn’t a direct function of the heart’s pumping action in the moment of systole; it’s regulated mainly by the tone of the peripheral vessels.