Systole

Contraction- and ejection period

Systole is that part of the cardiac cycle in which the ventricel is contracting and blood is ejected into the aorta. A distinction is drawn between a contraction- and an ejection phase of the systole. The ejection phase starts after the contraction phase, when pressure within the left and right ventricel exceeds that of the pulmonary artery and aorta. In that moment the pulmonary and aortic valves are opening.