Answer:
) a delay of the action potential at the atrioventricular node
Explanation:
The reason for the short delay of 0.9s. is to ensure maximum contractions of the atrial to eject blood into the relaxed ventricles.(ventricular filing).
Thus when the atrial is contracting,the ventricles relax and vice versa.The short duration for the artrial contraction to occur for blood ejection into the relax ventricles guarantee that artial systole can not overlap the ventricle systole.
The artial must contract first for the ventricle fillings,and when this is completed,the atrioventricular valves closes,and blood flow through the aorta to the systemic circulation from the left ventricle and into the pulmonary circulation through the pulmonary vein.
This occurs simultaneously with both the R and L Artrial,and right and left Ventricles.
