Ventricular filling

A. False   Atrial contraction accounts for only about 20 per cent of filling at rest.

B. False   During this phase the AV valves are closed and ventricular volume is constant.

C. True   This low-pitched sound is sometimes heard in early diastole.

D. False   Filling occurs when atrial pressure exceeds ventricular pressure.

E. True   Due to entry of blood accumulated in the atria during ventricular systole