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21 Cards in this Set
- Front
- Back
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How are the fibers arranged in cardiac muscle?
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bundles that cover 3 planes
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What happens during contraction in cardiac muscle?
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squeezes blood out
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What are the 2 types of cells in cardiac muscle?
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contractile cells
pacemaker cells |
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Characteristics of contractile cells? 6
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short
branched striated some t-tubules Sarcoplasmic Reticulum extensive mitochondria |
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Characteristics of pacemaker cells?
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thin
branched non-striated non contractile |
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What do cardiac cells communicate by?
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gap junctions called intercalated discs
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Steps to excitation contraction coupling? 4
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-excitation initiated by pacemaker cells
-excites contractile cells -cross bridge formation and contraction -shorten sarcomeres and blood is pumped out |
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What channels are in pacemaker cells to initiate cardiac action potential? 3
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-leaky Na+ channels
-fast Ca2+ channels -K+ channels |
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What channels are in contractile cells? 3
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-fast Na+ channels
-slow Ca2+ channels -K+ channels |
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What opens Na+ channels in contractile cells?
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Na+ leaking in from neighboring cells
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What causes Ca2+ channels to open in contractile cells?
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depolarization from Na+
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When does contraction of the cell occur?
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after action potential
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Sinoatrial node?
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70 - 75 bpm
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Atrioventricular node?
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50 bpm
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AV bundle?
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30 bpm
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Role of L & R bundle branches?
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take info to ventricles
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Role of Purkinje fiber?
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take message to contractile cells
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EKG: Isoelectric line?
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resting membrane potential
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EKG: P wave?
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represents atrial depolarization
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EKG: QRS? 2
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ventricular depolarization
atrial replorization |
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EKG: ST segment?
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ventricular repolorization
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