heart cycle

Question 1

ventricular filling- diastole

Answer 1

AV valves open
Semilunar closed

Driven by venous pressure

Ventricle walls expand as they fill

As soon as ventricular pressure exceeds atrial AV valves shut

Question 2

isovolumetric contraction

Answer 2

AV valves closed
Semilunar closed

Pressure in ventricles now begins to climb rapidly.

Question 3

ejection

Answer 3

AV valves closed
Semilunar open

When ventricular pressure > arterial pressure
semilunar valves pushed open

bulging of elastic arteries

Question 4

isovolumetric relaxation

Answer 4

Eventually rate at which blood is transported
to the peripheral arteries exceeds the blood leaving the ventricles so pressure in ventricles falls

Semilunar valves close

AV valves closed
Semilunar closed

Until ventricular pressure falls below atrial pressure

Then AV valves are pushed open and blood begins to fill ventricles again

Atria have already been filling