Term
| Cardiac muscle fibers are interconnected by intercalated discs. They form a functional syncytia that is: |
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Definition
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Term
| Depolarization in heart is due to |
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Definition
| Decreased outward K+ current |
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Term
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Definition
| L-type Ca++ channels and voltage-activated K+ channels |
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Term
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Definition
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Term
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Definition
| atria 70 bpm; ventricles 30 bpm |
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Term
| too much extracellular K+ ==> |
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Definition
| depolarize cell, ectopic foci and arrhythmias, stop heart |
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Term
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Definition
| blocks Ca influx to reduce contraction force |
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Term
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Definition
| Increase extracellular CA (increase contraction strength) |
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Term
| Isovolumetric ventricular contraction |
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Definition
| contraction w/o change in bld vol of heart |
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Term
| Isovolumetric Ventricular Relaxation |
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Definition
| no bld movement from atrium into vents until pressure is lower in vents than atrium |
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Term
| Norepinephrine released from sympathetic nerves bind___ |
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Definition
| B1 adrenergic receptrorc causing a decrease in K+ permeability in the SA node by accelerating inactivation of K+ channels |
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Term
| Acetlycholine_____ K+ permeability of SA node by_____. Results in___ |
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Definition
| increases; slowing closure of K+ channels. Decreased HR |
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Term
| Frank-Starling Law of the heart |
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Definition
| increased venous return results in increased stroke vol |
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Term
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Definition
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