Systole is the period of contraction of the ventricular muscles during that time blood is pumped into the pulmonary artery and the aorta.
Diastole is the period of dilation of the heart chambers as the blood fills the heart. For normal adult the systolic pressure is around 140 mm of Hg and diastolic pressure is around 80 mm of Hg. It is measured using noninvasive blood pressure measuring device called as Sphygmomanometer.