Cardiac Cycle and Valve Functions

The video tutorial explains the cardiac cycle, which lasts approximately 0.8 seconds and is divided into three steps: atrial and ventricular diastole, atrial systole, and ventricular systole. Each step is detailed with changes in pressure and volume, and the role of valves is highlighted. Graphs are used to illustrate the changes in ventricular and atrial pressure and volume throughout the cycle.

What is the duration of the entire cardiac cycle?

• 0.4 seconds

• 0.8 seconds

• 1.6 seconds

• 1.2 seconds

During atrial and ventricular diastole, what happens to the semilunar valves?

• They remain unchanged

• They open

• They partially open

• They close

What is the primary function of the semilunar valves during the cardiac cycle?

• To allow blood flow into the atria

• To prevent backflow into the ventricles

• To allow blood flow into the ventricles

• To prevent backflow into the atria

Which phase of the cardiac cycle involves both atrial and ventricular relaxation?

• Ventricular systole

• None of the above

• Atrial and ventricular diastole

• Atrial systole

What causes the slight increase in ventricular pressure during atrial systole?

• Ventricular contraction

• Atrial relaxation

• Atrial contraction

• Passive filling

How long does atrial systole last in the cardiac cycle?

• 0.1 seconds

• 0.2 seconds

• 0.4 seconds

• 0.3 seconds

Which valve opens due to increased ventricular pressure during ventricular systole?

• Atrioventricular valve

• Tricuspid valve

• Semilunar valve

• Mitral valve

What happens to the blood volume in the ventricles during ventricular systole?

• It fluctuates

• It remains constant

• It decreases

• It increases

What is the peak pressure reached in the ventricles during ventricular systole?

• 80 mmHg

• 100 mmHg

• 120 mmHg

• 140 mmHg

At the end of the cardiac cycle, which valve opens to allow passive filling?

• Semilunar valve

• Atrioventricular valve

• Pulmonary valve

• Aortic valve