1|Page
UCLA EKG STUDY GUIDE EXAM ||Verified
Exam!!!||Verified Exam!!!, Most Recent Exam 2026
Actual Complete Real Exam Questions And Correct
Answers (Verified Answers) Already Graded A+
!!Newest Exam!!!
Name the three different type of heart cells - Answers-
Allow the heart to integrate electrical and mechanical
activity of the heart
1. Pacemaker cells
2. Electrical conduction cells
3. Myocardial cells
What do pacemaker cells do? - Answers-Pacemaker cells
have the ability to initiate an impulse
(automaticity)
o Sinoatrial (SA) node:
o Atrioventricular (AV) node
o Purkinje fibers
o Every cell in the heart has automaticity, but normally
suppressed.
,2|Page
What do the electrical conduction cells do? - Answers-
Wires of the heart's electrical circuit
• Carry current rapidly and efficiently to distant regions of
the heart
What is electrical pathway of the heart starting from SA
node - Answers-Sinoatrial (SA) node ->Internodal
pathways ->Atrioventricular (AV) node->Bundle of His-
>Bundle branches -> Purkinje fibers
What is the pathophysiology of the SA node - Answers-SA
(Sinoatrial) Node • Located in the right atrium near
the superior vena cava
• Primary pacemaker • Inherent rate: 60-100 bpm •
Innervated by autonomic nervous
system
• Electrical impulses from SA node
"depolarizes" the atria via
internodal tracts and
Bachmannn's bundle, resulting in
atrial contraction.
,3|Page
What is the pathophysiology of the AV node? - Answers-
AV (Atrioventricular) Node • Located in the inferior right
atrium
• Responsible for slowing down
conduction from the atria to the
ventricles just long enough for
atrial contraction to occur
• Subsidiary pacemaker • Inherent rate: 40-60 bpm
What does it mean when the heart is electrically polarized
at rest? - Answers-The inside of the heart cell has a higher
potassium concentration, whereas the outside has a
higher concentration of sodium.
• The higher positive charge outside the cell causes a
relatively more negative charge inside the cell.
• The difference between the charges outside and inside of
the cell wall is known as its electrical potential.
What occurs during depolarization within the heart cell? -
Answers-Na+ moves into the cell rapidly in response to an
electrical impulse: Inside of cell loses negative
potential.
, 4|Page
Depolarization is propagated from cell to cell, transmitted
across the entire heart.
• The wave of depolarization represents a flow of
electricity.
What happens in repolarization of the heart? - Answers-
The ions return to their original resting state and the heart
cells restore their resting polarity.
List in phases the electrophysiology of the heart -
Answers-Phase 0: Na+ flow in and rapid depolarization
occurs
when stimulated
Phase 1: Rapid return to isoelectric level
Phase 2: Ca++ ions flow in and myocytes contract
Phase 3: K+ flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
What is the pathophysiology of the bundle of HIS? -
Answers-Divides into the right and left bundle branches
UCLA EKG STUDY GUIDE EXAM ||Verified
Exam!!!||Verified Exam!!!, Most Recent Exam 2026
Actual Complete Real Exam Questions And Correct
Answers (Verified Answers) Already Graded A+
!!Newest Exam!!!
Name the three different type of heart cells - Answers-
Allow the heart to integrate electrical and mechanical
activity of the heart
1. Pacemaker cells
2. Electrical conduction cells
3. Myocardial cells
What do pacemaker cells do? - Answers-Pacemaker cells
have the ability to initiate an impulse
(automaticity)
o Sinoatrial (SA) node:
o Atrioventricular (AV) node
o Purkinje fibers
o Every cell in the heart has automaticity, but normally
suppressed.
,2|Page
What do the electrical conduction cells do? - Answers-
Wires of the heart's electrical circuit
• Carry current rapidly and efficiently to distant regions of
the heart
What is electrical pathway of the heart starting from SA
node - Answers-Sinoatrial (SA) node ->Internodal
pathways ->Atrioventricular (AV) node->Bundle of His-
>Bundle branches -> Purkinje fibers
What is the pathophysiology of the SA node - Answers-SA
(Sinoatrial) Node • Located in the right atrium near
the superior vena cava
• Primary pacemaker • Inherent rate: 60-100 bpm •
Innervated by autonomic nervous
system
• Electrical impulses from SA node
"depolarizes" the atria via
internodal tracts and
Bachmannn's bundle, resulting in
atrial contraction.
,3|Page
What is the pathophysiology of the AV node? - Answers-
AV (Atrioventricular) Node • Located in the inferior right
atrium
• Responsible for slowing down
conduction from the atria to the
ventricles just long enough for
atrial contraction to occur
• Subsidiary pacemaker • Inherent rate: 40-60 bpm
What does it mean when the heart is electrically polarized
at rest? - Answers-The inside of the heart cell has a higher
potassium concentration, whereas the outside has a
higher concentration of sodium.
• The higher positive charge outside the cell causes a
relatively more negative charge inside the cell.
• The difference between the charges outside and inside of
the cell wall is known as its electrical potential.
What occurs during depolarization within the heart cell? -
Answers-Na+ moves into the cell rapidly in response to an
electrical impulse: Inside of cell loses negative
potential.
, 4|Page
Depolarization is propagated from cell to cell, transmitted
across the entire heart.
• The wave of depolarization represents a flow of
electricity.
What happens in repolarization of the heart? - Answers-
The ions return to their original resting state and the heart
cells restore their resting polarity.
List in phases the electrophysiology of the heart -
Answers-Phase 0: Na+ flow in and rapid depolarization
occurs
when stimulated
Phase 1: Rapid return to isoelectric level
Phase 2: Ca++ ions flow in and myocytes contract
Phase 3: K+ flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
What is the pathophysiology of the bundle of HIS? -
Answers-Divides into the right and left bundle branches
