This occurs when the ventricles are almost full the atria contracts, pumping more blood into the ventricles. The contraction completes ventricular filling, causing the pressure and volume in the ventricles to further increase. Following Atrial Systole is Ventricular Systole. This is when the ventricles contract, forcing blood back up towards the atria. When the pressure in the ventricles exceeds that in the atria it snaps the AV valves shut, causing the first heart sound, “lub.” The semilunar valves remain closed, trapping all the blood in the heart within the ventricles. It 's at this point in the cycle the heart contains the maximum amount of blood, known as the end-diastolic volume. The heart is going through Isovolumic Ventricular Contraction. This is when the ventricles are contracting, but the valves are closed. During this phase of the cardiac cycle, the pressure in both the ventricles are increasing, but the volume stays the same. When the pressure in the ventricle exceeds that of the aorta or arteries, the semilunar valves will
This occurs when the ventricles are almost full the atria contracts, pumping more blood into the ventricles. The contraction completes ventricular filling, causing the pressure and volume in the ventricles to further increase. Following Atrial Systole is Ventricular Systole. This is when the ventricles contract, forcing blood back up towards the atria. When the pressure in the ventricles exceeds that in the atria it snaps the AV valves shut, causing the first heart sound, “lub.” The semilunar valves remain closed, trapping all the blood in the heart within the ventricles. It 's at this point in the cycle the heart contains the maximum amount of blood, known as the end-diastolic volume. The heart is going through Isovolumic Ventricular Contraction. This is when the ventricles are contracting, but the valves are closed. During this phase of the cardiac cycle, the pressure in both the ventricles are increasing, but the volume stays the same. When the pressure in the ventricle exceeds that of the aorta or arteries, the semilunar valves will