During the systole phase of the cardiac cycle, high blood pressure in the ventricles forces the aortic valve to open. That is option 1.
What is cardiac cycle?
Cardiac cycle is defined as the phases of contraction and relaxation of the heart muscles which would lead to deoxygenation and oxygenation the blood for body use.
The stages of cardiac cycle include the following:
- Atrial systole: At this stage of cardiac cycle, the aortic valve and pulmonary artery closes and atrioventricular valves open
- Ventricular systole: At this stage, the contraction of the ventricles leads to the Pulmonary artery and aortic valve closure.
- Atrial diastole: At this stage, their is relaxation of the heart chambers which occurs when aortic valve and pulmonary artery closes and atrioventricular valves open.
- Ventricular diastole: At this stage, venous blood enters the left atrium, and when blood pressure within the left atrium exceeds blood pressure in the left ventricle, the mitral valve opens and passive filling of the ventricle occurs.
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