More than one choice may apply.
Soon after the onset of ventricular systole, the
a. AV valves close.
b. semilunar valves open.
c. first heart sound is heard.
d. aortic pressure increases.

검증된 단계별 안내

Understand the phases of the cardiac cycle: Ventricular systole refers to the contraction of the ventricles, which occurs after the ventricles fill with blood during diastole. This contraction generates pressure within the ventricles.

Analyze the behavior of the AV (atrioventricular) valves: During ventricular systole, the pressure in the ventricles exceeds the pressure in the atria, causing the AV valves (tricuspid and mitral valves) to close. This prevents backflow of blood into the atria.

Examine the semilunar valves: As ventricular pressure continues to rise during systole, it eventually exceeds the pressure in the arteries (aorta and pulmonary artery), causing the semilunar valves (aortic and pulmonary valves) to open, allowing blood to be ejected into the arteries.

Relate the first heart sound to valve closure: The first heart sound (S1) is produced by the closure of the AV valves at the beginning of ventricular systole. This sound is often described as a 'lub' sound.

Consider the effect on aortic pressure: As blood is ejected from the left ventricle into the aorta during systole, the pressure in the aorta increases. This is a direct result of the ventricular contraction and the opening of the aortic semilunar valve.

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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.

Ventricular Systole

Ventricular systole is the phase of the cardiac cycle when the ventricles contract, pumping blood into the aorta and pulmonary artery. This phase is crucial for maintaining blood circulation throughout the body. It begins after the atria have emptied their blood into the ventricles and is marked by a rapid increase in ventricular pressure.

Heart Valves

The heart contains four main valves: the atrioventricular (AV) valves and the semilunar valves. During ventricular systole, the AV valves close to prevent backflow into the atria, while the semilunar valves open to allow blood to flow into the arteries. Understanding the function of these valves is essential for grasping the mechanics of blood flow during the cardiac cycle.

Cardiac Sounds

The first heart sound, often described as 'lub,' occurs when the AV valves close at the beginning of ventricular systole. This sound is an important indicator of heart function and is used in clinical settings to assess cardiac health. The timing of this sound relative to the phases of the cardiac cycle is critical for understanding heart dynamics.

More than one choice may apply. Soon after the onset of ventricular systole, the a. AV valves close. b. semilunar valves open. c. first heart sound is heard. d. aortic pressure increases.