be230cLecture8

Purkinje fibers the lef and right bundle branchs fork

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Unformatted text preview: Atrioventricular Bundle •  A.K.A. Bundle of His –  From the AV node, impulses travel through to the right and lef bundle branches –  These branches extend to the right and lef sides of the septum and bohom of the heart. Purkinje Fibers –  The lef and right bundle branchs fork repeatedly to form the Purkinje fibers that transmit the impulses to working cardiomyocytes –  The bundle of His, bundle branches and Purkinje fibers transmit impulses quickly to coordinate L and R ventricular contracGon Intercellular Impulse PropagaGon •  •  •  Intercalated discs: gap juncGons and desmosomes. Gap juncGons permit Ca2+ and Na+ transfer between cells. Desmosomes provide structural integrity. During wave propagaGon, Na+ and Ca2+ entering a cardiomyocyte raise membrane potenGal and acGvate Na channels to fire the acGon potenGal T ­tubule network increases effecGve surface area for Ca2+ entry that sGmulates Ca2+ ­induced Ca2+ release from sarcoplasmic reGculum, amplifying Ca2+ release, and acGvaGng contracGon 3 4/25/13 Electrocardiogram •  Method developed by Wilhelm Einthoven –  Dutch Elektrokardiogram (EKG) –  Now usually ECG. •  Records ion movement in heart. –  VariaGons in electrical potenGal radiate from heart; detectable at wrists, ankles. Electrocardiogram •  P wave –  DepolarizaGon of atria –  Followed by contracGon •  QRS complex –  3 waves (Q, R, & S) –  DepolarizaGon of ventricles –  Followed by contracGon •  T wave –  RepolarizaGon of ventricles •  P ­Q interval • ...
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This document was uploaded on 04/09/2014.

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