The.................... Valves close shortly after the start of ventricular systole while the................. valves close shortly after the diastole starts

Explanation

To answer the question, we need to identify the specific valves that close during two phases of the cardiac cycle: ventricular systole and diastole.

1. **Identify the valves that close during ventricular systole**:
- During ventricular systole, the ventricles contract to pump blood out of the heart. To prevent backflow of blood into the atria, the **atrioventricular (AV) valves** close. The AV valves include the tricuspid valve (between the right atrium and right ventricle) and the bicuspid (or mitral) valve (between the left atrium and left ventricle).

2. **Identify the valves that close during diastole**:
- After the ventricles contract, they need to relax, which is known as diastole. During this phase, the blood is filling back into the ventricles from the atria. To prevent backflow of blood from the arteries into the ventricles, the **semilunar valves** close. The semilunar valves include the pulmonary valve (between the right ventricle and pulmonary artery) and the aortic valve (between the left ventricle and aorta).

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