9/8/25, 2:22 PM UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers) (Latest Update 2025) UPDATE!! UCLA EKG Study EX…
UCLA EKG STUDY GUIDE EXAM Questions and
Answers (Verified Answers) (Latest Update 2025)
UPDATE!! UCLA EKG Study EXAM
Save
Terms in this set (68)
The inside of the heart cell has a higher potassium
concentration, whereas the outside has a higher
concentration of sodium.
What does it mean when
• The higher positive charge outside the cell causes a
the heart is electrically
relatively more negative charge inside the cell.
polarized at rest?
• The difference between the charges outside and
inside of the cell wall is known as its electrical
potential.
Na+ moves into the cell rapidly in response to an
electrical impulse: Inside of cell loses negative
potential.
What occurs during
depolarization within the Depolarization is propagated from cell to cell,
heart cell? transmitted across the entire heart.
• The wave of depolarization represents a flow of
electricity.
What happens in The ions return to their original resting state and the
repolarization of the heart cells restore their resting polarity.
heart?
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,9/8/25, 2:22 PM UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers) (Latest Update 2025) UPDATE!! UCLA EKG Study EX…
Phase 0: Na+ flow in and rapid depolarization occurs
when stimulated
List in phases the
Phase 1: Rapid return to isoelectric level
electrophysiology of the
Phase 2: Ca++ ions flow in and myocytes contract
heart
Phase 3: K+ flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
Allow the heart to integrate electrical and mechanical
activity of the heart
Name the three different
1. Pacemaker cells
type of heart cells
2. Electrical conduction cells
3. Myocardial cells
Pacemaker cells have the ability to initiate an impulse
(automaticity)
o Sinoatrial (SA) node:
What do pacemaker cells
o Atrioventricular (AV) node
do?
o Purkinje fibers
o Every cell in the heart has automaticity, but normally
suppressed.
Wires of the heart's electrical circuit
What do the electrical
• Carry current rapidly and efficiently to distant
conduction cells do?
regions of the heart
What is electrical pathway Sinoatrial (SA) node ->Internodal pathways -
of the heart starting from >Atrioventricular (AV) node->Bundle of His->Bundle
SA node branches -> Purkinje fibers
SA (Sinoatrial) Node • Located in the right atrium near
the superior vena cava
• Primary pacemaker • Inherent rate: 60-100 bpm •
Innervated by autonomic nervous
What is the
system
pathophysiology of the SA
• Electrical impulses from SA node
node
"depolarizes" the atria via
internodal tracts and
Bachmannn's bundle, resulting in
atrial contraction.
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, 9/8/25, 2:22 PM UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers) (Latest Update 2025) UPDATE!! UCLA EKG Study EX…
AV (Atrioventricular) Node • Located in the inferior
right
atrium
What is the
• Responsible for slowing down
pathophysiology of the AV
conduction from the atria to the
node?
ventricles just long enough for
atrial contraction to occur
• Subsidiary pacemaker • Inherent rate: 40-60 bpm
Divides into the right and left bundle branches
What is the
• Impulses are conducted down the LBB faster than
pathophysiology of the
the RBB. The difference in conduction time allows
bundle of HIS?
both ventricles to contract at the same time.
Purkinje Fibers • Finger-like projections that extend
What is the from the bundle branches
pathophysiology of the • Send impulses into the myocardial tissues of the
Purkinje fibers? ventricles and causes them to contract
• Subsidiary pacemaker • Inherent rate: 20-40 bpm
The contractile machinery of the heart
• When a myocardial cell is depolarized,
What do the myocardial calcium is released within the cell,
cells do? causing the cell to contract.
• Myocardial cells transmit an electrical current,
but far less efficient.
•SA node (• 60-100 bpm)
What are the SA, AV, and
•AV node (• 40-60 bpm)
purkinje rates?
•Purkinje fibers (• 20-40 bpm)
Na: 135-146 mEq/L
What are the normal
• K: 3.6-5.3 mEq/L
electrolyte levels for
• Ca: 8.5-10.3 mg/dL
sodium, K, CA, ionized CA,
• Ionized Ca 1.09-1.29 mmol/L (Corrected:1.10 mmol/L)
Mg?
• Mg: 1.4 - 1.9mEq/L
https://quizlet.com/1073066473/ucla-ekg-study-guide-exam-questions-and-answers-verified-answers-latest-update-2025-update-ucla-ekg-study-exa… 3/26
UCLA EKG STUDY GUIDE EXAM Questions and
Answers (Verified Answers) (Latest Update 2025)
UPDATE!! UCLA EKG Study EXAM
Save
Terms in this set (68)
The inside of the heart cell has a higher potassium
concentration, whereas the outside has a higher
concentration of sodium.
What does it mean when
• The higher positive charge outside the cell causes a
the heart is electrically
relatively more negative charge inside the cell.
polarized at rest?
• The difference between the charges outside and
inside of the cell wall is known as its electrical
potential.
Na+ moves into the cell rapidly in response to an
electrical impulse: Inside of cell loses negative
potential.
What occurs during
depolarization within the Depolarization is propagated from cell to cell,
heart cell? transmitted across the entire heart.
• The wave of depolarization represents a flow of
electricity.
What happens in The ions return to their original resting state and the
repolarization of the heart cells restore their resting polarity.
heart?
https://quizlet.com/1073066473/ucla-ekg-study-guide-exam-questions-and-answers-verified-answers-latest-update-2025-update-ucla-ekg-study-exa… 1/26
,9/8/25, 2:22 PM UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers) (Latest Update 2025) UPDATE!! UCLA EKG Study EX…
Phase 0: Na+ flow in and rapid depolarization occurs
when stimulated
List in phases the
Phase 1: Rapid return to isoelectric level
electrophysiology of the
Phase 2: Ca++ ions flow in and myocytes contract
heart
Phase 3: K+ flow out and rapid depolarization occurs
Phase 4: Polarized resting phase
Allow the heart to integrate electrical and mechanical
activity of the heart
Name the three different
1. Pacemaker cells
type of heart cells
2. Electrical conduction cells
3. Myocardial cells
Pacemaker cells have the ability to initiate an impulse
(automaticity)
o Sinoatrial (SA) node:
What do pacemaker cells
o Atrioventricular (AV) node
do?
o Purkinje fibers
o Every cell in the heart has automaticity, but normally
suppressed.
Wires of the heart's electrical circuit
What do the electrical
• Carry current rapidly and efficiently to distant
conduction cells do?
regions of the heart
What is electrical pathway Sinoatrial (SA) node ->Internodal pathways -
of the heart starting from >Atrioventricular (AV) node->Bundle of His->Bundle
SA node branches -> Purkinje fibers
SA (Sinoatrial) Node • Located in the right atrium near
the superior vena cava
• Primary pacemaker • Inherent rate: 60-100 bpm •
Innervated by autonomic nervous
What is the
system
pathophysiology of the SA
• Electrical impulses from SA node
node
"depolarizes" the atria via
internodal tracts and
Bachmannn's bundle, resulting in
atrial contraction.
https://quizlet.com/1073066473/ucla-ekg-study-guide-exam-questions-and-answers-verified-answers-latest-update-2025-update-ucla-ekg-study-exa… 2/26
, 9/8/25, 2:22 PM UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers) (Latest Update 2025) UPDATE!! UCLA EKG Study EX…
AV (Atrioventricular) Node • Located in the inferior
right
atrium
What is the
• Responsible for slowing down
pathophysiology of the AV
conduction from the atria to the
node?
ventricles just long enough for
atrial contraction to occur
• Subsidiary pacemaker • Inherent rate: 40-60 bpm
Divides into the right and left bundle branches
What is the
• Impulses are conducted down the LBB faster than
pathophysiology of the
the RBB. The difference in conduction time allows
bundle of HIS?
both ventricles to contract at the same time.
Purkinje Fibers • Finger-like projections that extend
What is the from the bundle branches
pathophysiology of the • Send impulses into the myocardial tissues of the
Purkinje fibers? ventricles and causes them to contract
• Subsidiary pacemaker • Inherent rate: 20-40 bpm
The contractile machinery of the heart
• When a myocardial cell is depolarized,
What do the myocardial calcium is released within the cell,
cells do? causing the cell to contract.
• Myocardial cells transmit an electrical current,
but far less efficient.
•SA node (• 60-100 bpm)
What are the SA, AV, and
•AV node (• 40-60 bpm)
purkinje rates?
•Purkinje fibers (• 20-40 bpm)
Na: 135-146 mEq/L
What are the normal
• K: 3.6-5.3 mEq/L
electrolyte levels for
• Ca: 8.5-10.3 mg/dL
sodium, K, CA, ionized CA,
• Ionized Ca 1.09-1.29 mmol/L (Corrected:1.10 mmol/L)
Mg?
• Mg: 1.4 - 1.9mEq/L
https://quizlet.com/1073066473/ucla-ekg-study-guide-exam-questions-and-answers-verified-answers-latest-update-2025-update-ucla-ekg-study-exa… 3/26
