(a)[1]
State the exact position of the sinoatrial node in the heart.
(b)[1]
State the section of the cardiac cycle that is directly started by the wave of excitation released by the sinoatrial node.
(c)[2]
Control of the cardiac cycle includes the ventricles contracting after the atrial walls have completed contraction. Outline how this control is brought about.
(d)[1]
Name the heart valves that open shortly after the Purkyne tissue receives an impulse from the atrioventricular node.