SHARP EKG Exam Questions & A+
Solutions
1. myocardial muscle cells
2. myocardial pacemaker cells - Correct answer-What are the two basic kinds of
cardiac cells?
1. Automaticity
2. Excitability
3. Conductivity
4. Contractility - Correct answer-What are the 4 primary cell characteristics?
1. sodium
2. potassium - Correct answer-What are the two major ions that affect cardiac
function?
Potassium - Correct answer-What are the primary ions inside the cell?
Sodium - Correct answer-What are the primary ions outside the cell?
1. membrane channels
,2. concentration gradient
3. electrical gradient
4. sodium-potassium pump - Correct answer-Distribution of ions on either side of
the membrane is determined by which several factors?
In the upper wall of the right atrium/near the inlet of the superior vena cava -
Correct answer-Where is the SA node located?
60-100 bpm - Correct answer-What is the intrinsic rate of the SA node?
40-60 bpm - Correct answer-Pacemaker cells in the AV junction generate electrical
impulses at what rate?
1. slow conduction of the electrical impulse through the AV node to allow atria to
empty into the ventricles (atrial kick)
2. to serve as a back pack pacemaker
3. protect ventricles from fast rates - Correct answer-What are the 3 functions of
the AV node?
To the bundle of His - Correct answer-After the delay in the AV node, where does
the impulse go?
The Bundle of His (AV Bundle) runs from the AV node through the IV septum,
splitting into R. and L. branches and eventually breaking into Purkinje fibers as it
,spreads through the ventricular walls - Correct answer-What is the function of the
bundle of His?
30-40 bpm - Correct answer-What is the rate of electrical impulse the Purkinje
Fibers have?
atrial depolarization - Correct answer-What does the P wave represent?
during the QRS complex - Correct answer-When does atrial repolarization occur?
ventricular depolarization - Correct answer-What does the QRS wave represent?
early ventricular repolarization - Correct answer-What does the ST segment
represent?
ventricular repolarization - Correct answer-What does the T wave represent?
the time of *ventricular activity* including both depolarization and repolarization -
Correct answer-What does the QT interval represent?
1. Absolute refractory period
2. Relative refractory period - Correct answer-What are the two refectory phases of
the cardiac cycle?
The cardiac cells are unable to respond to an electrical stimulus (from the onset of
the QRS to the peak of the T wave) - Correct answer-What is "absolute refractory
period"?
, The cardiac cells have depolarized sufficiently to respond to a strong stimulus
(peak of T wave to end of T wave) - Correct answer-What is the "relative
refractory period"?
0.04 - Correct answer-A small square on EKG paper is how long?
0.2 - Correct answer-A big square on EKG paper is how long?
< .10 - Correct answer-How long is a P wave?
0.12-0.20 - Correct answer-What is the duration of the PR interval?
< .10 - Correct answer-What is the duration of the QRS?
1. a electrical impulse that originated in an ectopic site in the ventricles
2. BBB
3. an electrical impulse that went thru a accessory conduction pathway that
bypasses the AV node - Correct answer-What are some causes of a abnormally
wide QRS?
1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
Solutions
1. myocardial muscle cells
2. myocardial pacemaker cells - Correct answer-What are the two basic kinds of
cardiac cells?
1. Automaticity
2. Excitability
3. Conductivity
4. Contractility - Correct answer-What are the 4 primary cell characteristics?
1. sodium
2. potassium - Correct answer-What are the two major ions that affect cardiac
function?
Potassium - Correct answer-What are the primary ions inside the cell?
Sodium - Correct answer-What are the primary ions outside the cell?
1. membrane channels
,2. concentration gradient
3. electrical gradient
4. sodium-potassium pump - Correct answer-Distribution of ions on either side of
the membrane is determined by which several factors?
In the upper wall of the right atrium/near the inlet of the superior vena cava -
Correct answer-Where is the SA node located?
60-100 bpm - Correct answer-What is the intrinsic rate of the SA node?
40-60 bpm - Correct answer-Pacemaker cells in the AV junction generate electrical
impulses at what rate?
1. slow conduction of the electrical impulse through the AV node to allow atria to
empty into the ventricles (atrial kick)
2. to serve as a back pack pacemaker
3. protect ventricles from fast rates - Correct answer-What are the 3 functions of
the AV node?
To the bundle of His - Correct answer-After the delay in the AV node, where does
the impulse go?
The Bundle of His (AV Bundle) runs from the AV node through the IV septum,
splitting into R. and L. branches and eventually breaking into Purkinje fibers as it
,spreads through the ventricular walls - Correct answer-What is the function of the
bundle of His?
30-40 bpm - Correct answer-What is the rate of electrical impulse the Purkinje
Fibers have?
atrial depolarization - Correct answer-What does the P wave represent?
during the QRS complex - Correct answer-When does atrial repolarization occur?
ventricular depolarization - Correct answer-What does the QRS wave represent?
early ventricular repolarization - Correct answer-What does the ST segment
represent?
ventricular repolarization - Correct answer-What does the T wave represent?
the time of *ventricular activity* including both depolarization and repolarization -
Correct answer-What does the QT interval represent?
1. Absolute refractory period
2. Relative refractory period - Correct answer-What are the two refectory phases of
the cardiac cycle?
The cardiac cells are unable to respond to an electrical stimulus (from the onset of
the QRS to the peak of the T wave) - Correct answer-What is "absolute refractory
period"?
, The cardiac cells have depolarized sufficiently to respond to a strong stimulus
(peak of T wave to end of T wave) - Correct answer-What is the "relative
refractory period"?
0.04 - Correct answer-A small square on EKG paper is how long?
0.2 - Correct answer-A big square on EKG paper is how long?
< .10 - Correct answer-How long is a P wave?
0.12-0.20 - Correct answer-What is the duration of the PR interval?
< .10 - Correct answer-What is the duration of the QRS?
1. a electrical impulse that originated in an ectopic site in the ventricles
2. BBB
3. an electrical impulse that went thru a accessory conduction pathway that
bypasses the AV node - Correct answer-What are some causes of a abnormally
wide QRS?
1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
