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Cards In This Set
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Cardiac impulses are generated within the heart by the pacemaker system, doesnt need nervous system.
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Automaticity
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The frequency and regularity of pacemaking activity are also intrinsic to the heart
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Rhythmicity
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Myocardial tissue comprises a __________, thus, contraction occurs as an all or non response
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Functional syncytium
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The period during which the muscle fails to respond to a stiumlus of threshold intensity
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Refractory period
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Similar to skeletal muscle, contractile cells of the myocardium must be lectrically actived via _________.
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Action potential
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_____ activity initiates_______activity of the heart.
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Electrical. mechanical
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Independent, but coordinated, activity of the heart is a function of ________ and__________
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Gap junctions. intrinsic conduction system.
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Consists of noncontractile cardiac cells specialized to initiate and distribute impulses throughout the heart, so that it depolarizes and contracts in an orderly, sequential manner.
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Intrinsic conduction system
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Aka as pacemaker cells, provide the initial stiumulus for cardiac muscle contraction through their ability tto self generate an action potential
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Autorhythmic cells
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Initiate the action potentials that spread throughout the heart to trigger its rhythmic contractions
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Pacemaker potentials
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The pacemaker potential is attributed to special properties of the__________
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Na+ channels in the sarcolemma
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Depolarization and repolarization events involve the exchange of ___ and _____
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Na+ and K+
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The rapid depolarization that occurs during the action potential is caused by the____________
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Rapid influx of CA2+ from the extracellular space
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The initiating action potential originates from the_______
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SA node
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Main pacemaker of the heart
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Sinoatrial node (SA node)
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