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14 Cards in this Set
- Front
- Back
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SA node |
Triggers Cardiac cycle Responsible for regularity Fires to left and right atrium 60-100 rate Why rhythms are referred to as sinus rhythms |
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AV node |
Slower than SA 40-60 rate Can fill in if SA node disrupted but rhythm no longer sinus rhythm Maintains SA node rate |
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Depolarization (systole) |
Contraction of heart Sodium potassium pump Na flows INTO cell K flows OUT cell Calcium Channels open Increases time period of action potential - allows for longer stronger contractions |
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Repolarization (Diastole) |
Relaxation Sodium potassium channels close Outside of cell returns to negative |
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Chronotrope |
Heart rate Positive increases Negative decreases |
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Ionotrope |
Squeeze/contraction Positive makes harder squeeze Negative decreases squeeze |
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Dromotrope |
Hearts ability to carry electrical signal Positive increases ability Negative decreases ability/disrupts conduction |
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Absolute refractory period |
Cardiac cells can not be stimulated to depolarize Only time can not depolarize is when already depolarizing |
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Relative refractory period |
DANGEROUS Cells have repolarized to thier threshold potential Can be deparized with a strong stimulus T WAVE |
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P wave |
Atrial contraction/deparization |
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QRS complex |
Ventricle deparization/contraction |
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T wave |
Ventricle relaxation/repolarization Most sensitive time |
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U wave |
Final phase of repolarization Sometimes not seen Seen in slow heart rates |
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Isometric line |
No electrical activity Asystole Measurement line |
