The intrinsic conduction system ensures a coordinated and efficient heartbeat. If the sinoatrial (SA) node malfunctions, which part of the heart’s conduction system is most likely to take over as the pacemaker?

The AV node delay:

a. allows the atria and ventricles to depolarize and contract as a unit.

b. allows the two ventricles to depolarize and contract separately.

c. allows the atria and ventricles to depolarize and contract separately.

d. speeds up the impulse transmission from the atria to the ventricles.

A newer drug, Ivabradine, lowers the heart rate by blocking the nonselective HCN cation channels. Why would this action decrease the heart rate? Would this drug have an effect on pacemaker cells, contractile cells, or both? Explain.

Which feature of cardiac tissue allows for the rapid spread of action potentials through the heart?

Which statement best describes intrinsic conduction of the heart?

Which answer choice below correctly matches the cardiac conduction structure to where it’s found in the heart?

The AV node has fewer gap junctions than the SA node, leading to slower conduction. How does this slower conduction help the heart function?

What is the primary function of the pacemaker cells in the SA node in the heart?

Which structure or structures are most directly responsible for allowing contraction of the ventricles to begin at the apex of the heart rather than in the septum closer to the AV node?