Define cardiac cycle, and follow the events of one cycle.

검증된 단계별 안내

Begin by defining the cardiac cycle as the sequence of mechanical and electrical events that repeat with every heartbeat, including the contraction and relaxation of the atria and ventricles.

Explain that the cardiac cycle consists of two main phases: systole (contraction) and diastole (relaxation), which occur in both the atria and ventricles but at different times.

Describe the first event: atrial systole, where the atria contract to push blood into the ventricles, completing ventricular filling.

Next, outline ventricular systole, where the ventricles contract, causing the atrioventricular (AV) valves to close (producing the first heart sound) and the semilunar valves to open, allowing blood to be ejected into the arteries.

Finally, explain ventricular diastole, where the ventricles relax, the semilunar valves close (producing the second heart sound), and the AV valves open to allow passive filling of the ventricles, completing the cycle.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Cardiac Cycle

The cardiac cycle refers to the complete sequence of events in the heart from the beginning of one heartbeat to the start of the next. It includes phases of contraction and relaxation that enable blood to be pumped throughout the body.

Phases of the Cardiac Cycle

The cardiac cycle consists mainly of systole (contraction) and diastole (relaxation). During atrial systole, atria contract to fill ventricles; ventricular systole follows, pumping blood out; diastole allows chambers to relax and refill.

Heart Valve Function During the Cycle

Heart valves regulate blood flow direction during the cardiac cycle. The atrioventricular valves open during diastole to allow ventricular filling and close during systole to prevent backflow, while semilunar valves open during ventricular systole to eject blood.