Is the phase of the cardiac cycle that refers to contraction of the heart muscle systole, diastole, stroke volume, or none of these?
Systole is a term that refers to the contraction phase of the cardiac cycle.
Diastole is when the heart is relaxed.
Stroke volume is the amount of blood that exits the heart during a single contraction.
A nurse or physician may measure your blood pressure and tell you that you have a blood pressure of 120/80. What that means is that when your ventricles contract, a pressure of 120 mmHg is exerted against the walls of your blood vessels. This is your systolic blood pressure.
The denominator, 80, means that when your ventricles are relaxed, a pressure of 80 mmHg is exerted against your blood vessels. This is your diastolic blood pressure.