IB 6.2 Cardiac Cycle and Pressure Changes

A heart beat is initiated by the [?]

Because the heart beats on its own it is described as [?]

Which of the following is true?

• All four chambers of the heart contract simultaneously

• The atria contract simultaneously and the ventricles contract simultaneously

• Contraction of the chambers controls the opening and closing of valves

• The opening of valves creates the sound of your heart beat

Which of the following occurs between atrial systole and diastole?

• AV valves open

• AV valves close

• SL valves open

• SL valves close

What causes AV valves to open?

• Higher pressure in atria than ventricles

• Higher pressure in ventricles than atria

• Lower pressure in atria than ventricles

• Lower pressure in ventricles than atria

What causes AV valves to close?

• Higher pressure in atria than ventricles

• Higher pressure in ventricles than atria

• Lower pressure in atria than ventricles

• Lower pressure in ventricles than atria

What causes increased pressure in the aorta during contraction of the ventricles?

• Opening of the SL valve

• Closing of the SL valve

• Opening of the AV valves

• Closing of the AV valves

What causes the greatest increase in pressure during a cardiac cycle?

• Atrial systole

• Atrial diastole

• Ventricular systole

• Ventricular diastole