18. The Heart

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?

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?

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?

Which center in the medulla oblongata controls the sympathetic neurons that stimulate the heart?

Which statement best describes a difference between how the sympathetic and parasympathetic nervous system affects the heart?

How do pacemaker cardiac muscle cells differ from contractile cardiac muscle cells? What is autorhythmicity?