Normal conduction system properties/intervals Flashcards
What is the primary function of the heart’s conduction system?
To initiate and propagate electrical impulses for heart contraction.
True or False: The sinoatrial (SA) node is known as the heart’s natural pacemaker.
True
Fill in the blank: The __________ node is responsible for delaying the electrical impulse before it enters the ventricles.
atrioventricular (AV)
What is the normal heart rate range initiated by the SA node?
60 to 100 beats per minute.
What is the conduction velocity through the Purkinje fibers?
Approximately 2 to 4 meters per second.
Multiple Choice: Which part of the conduction system is responsible for ventricular contraction?
C. Purkinje fibers
What is the role of the bundle of His in the conduction system?
To conduct impulses from the AV node to the right and left bundle branches.
True or False: The AV node can act as a secondary pacemaker if the SA node fails.
True
What is the refractory period in cardiac conduction?
The time during which the heart muscle cannot be stimulated to contract again.
Fill in the blank: The __________ interval measures the time from the beginning of atrial depolarization to the beginning of ventricular depolarization.
PR
What does the QRS complex represent in an ECG?
Ventricular depolarization.
Multiple Choice: Which interval represents the time it takes for the ventricles to depolarize and repolarize?
B. QT interval
What is the significance of the ST segment in an ECG?
It represents the period between ventricular depolarization and repolarization.
True or False: The normal duration of the QRS complex is less than 0.12 seconds.
True
Fill in the blank: A prolonged __________ interval can indicate a delay in ventricular repolarization.
QT
What is the typical duration of the PR interval?
0.12 to 0.20 seconds.
Multiple Choice: Which structure conducts electrical impulses directly to the ventricles?
A. Bundle branches
What is the role of the SA node in the conduction system?
To generate electrical impulses that initiate the heartbeat.
True or False: The conduction system allows for coordinated contraction of the heart muscle.
True
What does the term ‘ectopic focus’ refer to in cardiac conduction?
An abnormal pacemaker outside the SA node.
Fill in the blank: The __________ fibers are specialized for rapid conduction of impulses throughout the ventricles.
Purkinje
What is the normal duration of the ST segment?
It varies but is typically less than 0.12 seconds.
Multiple Choice: Which interval indicates the time between the end of atrial depolarization and the beginning of ventricular repolarization?
C. QT interval
What is the primary consequence of a blocked conduction pathway in the heart?
It can lead to arrhythmias or ineffective heartbeats.
