SYSTOLE (CONTRACTION)
Phase when ventricles contract.
A trioventricular valves close preventing back- flow into the auricles.
Volume of the ventricles decreases while pressure increases to force blood out of the heart to the:
(i)Lungs via semi-lunar valves through the pulmonary artery
(ii)Body tissues except the lungs via the semi-lunar valves through the aorta.
The thick cardiac muscles of the left which left ventricles which generate high pressure which forces the blood to the furthest tissue in the body .