In order for blood to be delivered to the body (i.e. the systemic circuit), enough pressure must be developed by the ___________ to push open the ________________.

Question

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Valves are located between the atria and ventricles in order to control blood flow and prevent back-flow. They also exist between the ventricles and the arteries that lead to the lungs and body. Valves prevent back-flow by opening when it is time for blood to move from one chamber of the heart to the next, and closing after the blood has moved into the next chamber or artery. Valves are necessary for closing off the chambers so that adequate pressure can build up within the chambers. This pressure is necessary to ensure blood can reach its destinations. Valves must be closed on order for pressure to build up. Since the left ventricle is the main pump for systemic circulation, the pressure buildup from the blood in the closed chamber and the myocardium contraction must work together to create adequate pressure to push open the semilunar valve at the entrance to the aorta.
This same process occurs in the right side of the heart with the right ventricle and the pulmonary semilunar valve, however the right side supplies blood only to the lungs, not the systemic circuit.

In Order for Blood to Be Delivered to the Body