Electrical Conduction System of the Heart - Video Tutorials & Practice Problems
Intrinsic Cardiac Conduction System
Which feature of cardiac tissue allows for the rapid spread of action potentials through the heart?
Nodes.
Myelin sheaths.
Pacemaker Cells.
Gap junctions.
Which statement best describes intrinsic conduction of the heart?
Cells within the heart can initiate and transmit action potentials without nervous system input.
Cells in the heart can beat continually without fatigue.
Cells in the heart follow a specific rhythm that is set by the brain stem.
Cells in the heart pass action potentials between cells using gap junctions instead of neurotransmitters.
Anatomy of the Intrinsic Cardiac Conduction System
Electrical Conduction System of the Heart Example 1
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?
Atrioventricular (AV) node.
Bundle of His.
Purkinje Fibers.
Atrial muscle cells.
Which answer choice below correctly matches the cardiac conduction structure to where it’s found in the heart?
Atrioventricular node: left ventricle.
Purkinje fibers: left atrium.
Sinoatrial node: left atrium.
Right and left bundle fibers: septum.
Conduction Pathway and Contraction
Electrical Conduction System of the Heart Example 2
The AV node has fewer gap junctions than the SA node, leading to slower conduction. How does this slower conduction help the heart function?
Ensures that the ventricles have enough time to fill with blood before they contract.
Initiates the electrical impulse in the heart.
Conducts the impulse rapidly to the bundle of His.
Allows the ventricles to beat at a slower rate than the atria.
What is the primary function of the pacemaker cells in the SA node in the heart?
Slow the action potentials to allow for a 100 ms delay.
Regulation of blood pressure in the right atrium.
Rhythmic generation of action potentials.
Conduction of action potentials throughout the atria.
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?
Purkinje fibers.
Sinoatrial and atrioventricular nodes.
AV bundle and the left and right bundle branches.
Atrial conducting fibers.
Control of Heart Rate
Electrical Conduction System of the Heart Example 3
Which center in the medulla oblongata controls the sympathetic neurons that stimulate the heart?
Cardioinhibitory center.
Cardiorespiratory center.
Vagus center.
Cardioacceleratory center.
Which statement best describes a difference between how the sympathetic and parasympathetic nervous system affects the heart?
The sympathetic nervous system affects heart rate, while the parasympathetic nervous system affects contractility.
The sympathetic nervous system affects contractility and heart rate, while the parasympathetic only affects heart rate.
Both the sympathetic and parasympathetic nervous systems affect contractility, while the parasympathetic also affects heart rate.
Heart rate is controlled by the parasympathetic nervous system, while the sympathetic nervous system controls contractility.
Do you want more practice?
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