What is the period of contraction, during which the heart pumps blood into circulation, called?

1. The cardiac cycle alternates between two basic mechanical states in both atria and ventricles. 2. The period of contraction during which the heart pumps blood into circulation is called systole. 3. The period of relaxation, during which the chambers fill with blood, is called diastole. 4. Isovolumic relaxation is a specific early phase of ventricular diastole, and the refractory period is an electrical property of cardiac cells, neither of which is the general term for the contraction phase. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 19 "The Cardiovascular System: The Heart", section 19.3, p. 860_