MEAS 238/239 - CHAPTER 49 EXAM
QUESTIONS AND ANSWERS
Depolarization - Correct Answers -The electrical impulse that initiates a chain reaction
resulting in contraction.
Sinoatrial (SA) node (pacemaker) - Correct Answers -Electrical impulses occur at a rate
of 60 to 100 beats per minute, initiating the heartbeat with an electrical impulse that
causes depolarization.
Atrioventricular (AV) node - Correct Answers -Delays the electrical impulse to allow for
the atria to complete their contraction and ventricles to fill before the next contraction;
also serves as a secondary pacemaker if the SA node fails.
Bundle of His (AV bundle) - Correct Answers -Conducts electrical impulses from the
atria to the ventricles.
Bundle branches - Correct Answers -Conduct impulses down both sides of the
interventricular septum.
Purkinje fibers (network) - Correct Answers -Distribute the electrical impulses
throughout the right and left ventricles.
P wave - Correct Answers -Atrial depolarization with resulting atrial contraction.
QRS complex - Correct Answers -Ventricular depolarization and resulting ventricular
contraction (larger than the P wave); atrial repolarization occurs (not seen).
T wave - Correct Answers -Ventricular repolarization.
U wave - Correct Answers -Repolarization of the bundle of His and Purkinje fibers (not
always seen); may be seen in instances of electrolyte imbalance.
PR interval - Correct Answers -Beginning of atrial depolarization to the beginning of
ventricular depolarization.
QT interval - Correct Answers -Period of time from the start of ventricular depolarization
to the end of ventricular repolarization.
QUESTIONS AND ANSWERS
Depolarization - Correct Answers -The electrical impulse that initiates a chain reaction
resulting in contraction.
Sinoatrial (SA) node (pacemaker) - Correct Answers -Electrical impulses occur at a rate
of 60 to 100 beats per minute, initiating the heartbeat with an electrical impulse that
causes depolarization.
Atrioventricular (AV) node - Correct Answers -Delays the electrical impulse to allow for
the atria to complete their contraction and ventricles to fill before the next contraction;
also serves as a secondary pacemaker if the SA node fails.
Bundle of His (AV bundle) - Correct Answers -Conducts electrical impulses from the
atria to the ventricles.
Bundle branches - Correct Answers -Conduct impulses down both sides of the
interventricular septum.
Purkinje fibers (network) - Correct Answers -Distribute the electrical impulses
throughout the right and left ventricles.
P wave - Correct Answers -Atrial depolarization with resulting atrial contraction.
QRS complex - Correct Answers -Ventricular depolarization and resulting ventricular
contraction (larger than the P wave); atrial repolarization occurs (not seen).
T wave - Correct Answers -Ventricular repolarization.
U wave - Correct Answers -Repolarization of the bundle of His and Purkinje fibers (not
always seen); may be seen in instances of electrolyte imbalance.
PR interval - Correct Answers -Beginning of atrial depolarization to the beginning of
ventricular depolarization.
QT interval - Correct Answers -Period of time from the start of ventricular depolarization
to the end of ventricular repolarization.
