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The Heart: Structure and Function
1. Atrial Systole: The Atria begins to fill with blood, when the pressure in the
atria is higher then the pressure in the ventricles the Atrioventricular (AV)
Blood is forced into the Ventricles. The AV valves close to prevent
1. Ventricular Systole: When the pressure in the ventricles exceeds that of
the Aorta the semi lunar valves open, and blood flows into the arteries.
2. Diastole: All chambers relax the pressure of blood causes the semi
lunar valves to close preventing backflow into ventricles.
The blood pressure in the aorta is higher than in the pulmonary artery.
Explain what causes the blood pressure in the aorta to be higher. (1)