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1. What are the two basic kinds of 1. myocardial muscle cells
cardiac cells? 2. myocardial pacemaker cells
2. What are the 4 primary cell char- 1. Automaticity
acteristics? 2. Excitability
3. Conductivity
4. Contractility
3. What are the two major ions 1. sodium
that affect cardiac function? 2. potassium
4. What are the primary ions in- Potassium
side the cell?
5. What are the primary ions out- Sodium
side the cell?
6. Distribution of ions on either 1. membrane channels
side of the membrane is deter- 2. concentration gradient
mined by which several factors? 3. electrical gradient
4. sodium-potassium pump
7. Where is the SA node located? In the upper wall of the right atrium/near the inlet of the
superior vena cava
8. What is the intrinsic rate of the 60-100 bpm
SA node?
9. Pacemaker cells in the AV junc- 40-60 bpm
tion generate electrical impuls-
es at what rate?
10. What are the 3 functions of the 1. slow conduction of the electrical impulse through the AV
AV node? node to allow atria to empty into the ventricles (atrial kick)
, SHARP EKG
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2. to serve as a back pack pacemaker
3. protect ventricles from fast rates
11. After the delay in the AV node, To the bundle of His
where does the impulse go?
12. What is the function of the bun- The Bundle of His (AV Bundle) runs from the AV node
dle of His? through the IV septum, splitting into R. and L. branches
and eventually breaking into Purkinje fibers as it spreads
through the ventricular walls
13. What is the rate of electrical im- 30-40 bpm
pulse the Purkinje Fibers have?
14. What does the P wave repre- atrial depolarization
sent?
15. When does atrial repolarization during the QRS complex
occur?
16. What does the QRS wave repre- ventricular depolarization
sent?
17. What does the ST segment rep- early ventricular repolarization
resent?
18. What does the T wave repre- ventricular repolarization
sent?
19. What does the QT interval rep- the time of *ventricular activity* including both depolariza-
resent? tion and repolarization
20. What are the two refectory 1. Absolute refractory period
phases of the cardiac cycle? 2. Relative refractory period
, SHARP EKG
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21. What is "absolute refractory pe- The cardiac cells are unable to respond to an electrical
riod"? stimulus (from the onset of the QRS to the peak of the T
wave)
22. What is the "relative refractory The cardiac cells have depolarized sufficiently to respond to
period"? a strong stimulus (peak of T wave to end of T wave)
23. A small square on EKG paper is 0.04
how long?
24. A big square on EKG paper is 0.2
how long?
25. How long is a P wave? < .10
26. What is the duration of the PR 0.12-0.20
interval?
27. What is the duration of the QRS? < .10
28. What are some causes of a ab- 1. a electrical impulse that originated in an ectopic site in
normally wide QRS? the ventricles
2. BBB
3. an electrical impulse that went thru a accessory conduc-
tion pathway that bypasses the AV node
29. What are some causes of a ST 1. STEMI
elevation? 2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
30. What are some causes of ST de- 1) NSTEMI
pression? 2) Digoxin