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14 Cards in this Set
- Front
- Back
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Which artery supplies blood to the SA node?
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circumflex artery
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What are the three internodal pathways between the SA node and the AV node?
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• Anterior (Bachmann's)
• Middle (Wenckebach's) • Posterior (Thorel's) |
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Which artery supplies blood to the AV node in the majority of people?
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right coronary artery
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Which arteries provide blood flow to the bundle of His?
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braches from the anterior and posterior descending coronary arteries
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What occurs during depolarization?
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• cell membrane suddenly becomes selectively permeable to sodium
• sodium ions enter the cell resulting in a sharp rise of intracellular potential |
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What occurs during repolarization?
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• reestablishment of the resting membrane potential
• membrane permeability to potassium increases allowing potassium ions to move outward across the membrane |
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Name and describe the 5 phases of cardiac action potential?
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• Phase 0: fast sodium channels in the cell membrane are stimulated to open, resulting in the rapid influx of sodium
• Phase 1: signifies inactivation of the fast sodium channels w/ an abrupt decrease in sodium permeability • Phase 2: plateau phase; influx of calcium into the cell through slow Ca channels; coincides with ST segment • Phase 3: rapid depolarization; influx of calcium and sodium stops; increase in potassium permeability; potassium moves out • Phase 4: resting membrane potential |
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What does the P wave represent?
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atrial depolarization
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What does the PR segment represent?
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delay in AV node
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What does the QRS represent?
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ventricular depolarization
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What does the T wave represent?
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ventricular repolarization
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Name and describe the 4 inherent poroperties of the cardiac conduction system that can contribute to arrhythmias
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• automaticity: the ability of certain cells to initate an impulse or action potential spontaneously
• excitability: the ability of a cell to respond to an impulse and generate an action potential • conductivity: the ability to conduct impulses • refractoriness: the extent to which the cell is able to respond to an incoming stimulus |
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What is pulse deficit?
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the difference between the apical rate and the palpable peripheral pulses
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What is the most common chronic arrhythmia?
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atrial fibrillation
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