CBSE Class 10 Answered
Systole is the contraction of heart chambers, driving blood out of the chambers. Systole is initiated by the sinoatrial node, which is the heart's natural pacemaker. These cells are activated spontaneously by depolarization of their membranes. During systole, blood is driven through the aorta and pulmonary artery after each dilation or diastole.
Diastole is the period of time when the heart relaxes after systole.
When the pressure in the left ventricle drops to below the pressure in the left atrium, the mitral valve opens, causing accumulated blood from the atrium to flow into the ventricle.
Diastolic pressure refers to the lowest pressure within the arterial blood stream occurring during each heart beat, whereas systolic pressure refers to the highest arterial pressure during each heart beat.
When stating blood pressure, systole and then diastole is mentioned; for example: 120/80.