UCLA EKG STUDY GUIDE EXAM Questions and Answers (Verified Answers)

UCLA EKG STUDY GUIDE EXAM Questions
and Answers (Verified Answers)


What does it mean when the heart is electrically polarized at rest? - CORRECT
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ANSWER✔✔-The inside of the heart cell has a higher potassium concentration,
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whereas the outside has a higher concentration of sodium.
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• The higher positive charge outside the cell causes a relatively more negative
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charge inside the cell.
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• The difference between the charges outside and inside of the cell wall is known
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as its electrical potential.
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What occurs during depolarization within the heart cell? - CORRECT ANSWER✔✔-
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Na+ moves into the cell rapidly in response to an electrical impulse: Inside of cell
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loses negative
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potential.


Depolarization is propagated from cell to cell, transmitted across the entire heart.
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• The wave of depolarization represents a flow of electricity.
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What happens in repolarization of the heart? - CORRECT ANSWER✔✔-The ions
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return to their original resting state and the heart cells restore their resting
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polarity.

,List in phases the electrophysiology of the heart - CORRECT ANSWER✔✔-Phase 0:
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Na+ flow in and rapid depolarization occurs
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when stimulated |




Phase 1: Rapid return to isoelectric level
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Phase 2: Ca++ ions flow in and myocytes contract
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Phase 3: K+ flow out and rapid depolarization occurs
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Phase 4: Polarized resting phase
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Name the three different type of heart cells - CORRECT ANSWER✔✔-Allow the
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heart to integrate electrical and mechanical
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activity of the heart | | |




1. Pacemaker cells
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2. Electrical conduction cells
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3. Myocardial cells
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What do pacemaker cells do? - CORRECT ANSWER✔✔-Pacemaker cells have the
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ability to initiate an impulse
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(automaticity)
o Sinoatrial (SA) node:
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o Atrioventricular (AV) node
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o Purkinje fibers
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o Every cell in the heart has automaticity, but normally suppressed.
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, What do the electrical conduction cells do? - CORRECT ANSWER✔✔-Wires of the
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heart's electrical circuit
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• Carry current rapidly and efficiently to distant regions of the heart
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What is electrical pathway of the heart starting from SA node - CORRECT
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ANSWER✔✔-Sinoatrial (SA) node ->Internodal pathways ->Atrioventricular (AV) | | | | | | |


node->Bundle of His->Bundle branches -> Purkinje fibers
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What is the pathophysiology of the SA node - CORRECT ANSWER✔✔-SA
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(Sinoatrial) Node • Located in the right atrium near
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the superior vena cava
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• Primary pacemaker • Inherent rate: 60-100 bpm • Innervated by autonomic
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nervous
system
• Electrical impulses from SA node
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"depolarizes" the atria via | | |




internodal tracts and | |




Bachmannn's bundle, resulting in | | |




atrial contraction.
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What is the pathophysiology of the AV node? - CORRECT ANSWER✔✔-AV
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(Atrioventricular) Node • Located in the inferior right | | | | | | |




atrium
• Responsible for slowing down
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conduction from the atria to the | | | | |