Answer the following questions based upon your analysis of the heart's electrical conduction system:

1) There is a delay in time between the contraction of the atria and the contraction of the ventricles. This is called the AV-delay. What structural characteristics (identify more than one!) of the conducting fibers between the AV node and AV bundle help create the AV-delay?

2) The ventricles begin to contract from the apex first, and contraction continues superiorly "up" the walls of the ventricles. Why is it important that the ventricles contract from the apex "upward?"