1 / 8

Lab 2

Lab 2. The Intrinsic Cardiac Conduction System. Figure 18.14 Cardiac intrinsic conduction system and action potential succession during one heartbeat. Superior vena cava. Right atrium. 1. The sinoatrial (SA) node (pacemaker) generates impulses. Pacemaker potential.

rooney-carey
Download Presentation

Lab 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lab 2 The Intrinsic Cardiac Conduction System Mickey Dufilho

  2. Figure 18.14 Cardiac intrinsic conduction system and action potential succession during one heartbeat. Superior vena cava Right atrium 1 Thesinoatrial (SA) node (pacemaker) generates impulses. Pacemaker potential Internodal pathway SA node Left atrium 2 The impulses pause (0.1 s) at the atrioventricular (AV) node. Atrial muscle Purkinje fibers 3 The atrioventricular (AV) bundle connects the atria to the ventricles. AV node Pacemaker potential Ventricular muscle 4 Inter- ventricular septum Thebundle branches conduct the impulses through the interventricular septum. Plateau 5 ThePurkinje fibers depolarize the contractile cells of both ventricles. Milliseconds (a) Anatomy of the intrinsic conduction system showing the sequence of electrical excitation (b) Comparison of action potential shape at various locations Mickey Dufilho

  3. Figure 18.13 Pacemaker and action potentials of autorhythmic cells of the heart. Threshold Action potential 2 2 3 1 1 Pacemaker potential 3 2 1 Repolarization is due to Ca2+ channels inactivating and K+ channels opening. This allows K+ efflux, which brings the membrane potential back to its most negative voltage. Depolarization The action potential begins when the pacemaker potential reaches threshold. Depolarization is due to Ca2+ influx through Ca2+ channels. Pacemaker potential This slow depolarization is due to both opening of Na+ channels and closing of K+ channels. Notice that the membrane potential is never a flat line. Mickey Dufilho

  4. SA node Depolarization Repolarization R R T P T P Q S Atrial depolarization, initiated by the SA node, causes the P wave. 1 Q S 4 Ventricular depolarization is complete. R AV node R T P T P Q S Q 2 With atrial depolarization complete, the impulse is delayed at the AV node. S 5 Ventricular repolarization begins at apex, causing the T wave. R R T P T P Q S Q S 3 Ventricular depolarization begins at apex, causing the QRS complex. Atrial repolarization occurs. 6 Ventricular repolarization is complete. Mickey Dufilho

  5. QRS complex Sinoatrial node Ventricular depolarization Ventricular repolarization Atrial depolarization Atrioventricular node S-T Segment P-Q Interval Q-T Interval Mickey Dufilho

  6. Mickey Dufilho Figure 18.18

  7. Figure 18Cardiac intrinsic conduction system and action potential succession during one heartbeat. Superior vena cava Right atrium 1 Thesinoatrial (SA) node (pacemaker) generates impulses. Pacemaker potential Internodal pathway SA node Left atrium 2 The impulses pause (0.1 s) at the atrioventricular (AV) node. Atrial muscle Purkinje fibers 3 The atrioventricular (AV) bundle connects the atria to the ventricles. AV node Pacemaker potential Ventricular muscle 4 Inter- ventricular septum Thebundle branches conduct the impulses through the interventricular septum. Plateau 5 ThePurkinje fibers depolarize the contractile cells of both ventricles. Milliseconds (a) Anatomy of the intrinsic conduction system showing the sequence of electrical excitation (b) Comparison of action potential shape at various locations Mickey Dufilho

  8. Pacemaker http://www.youtube.com/watch?v=8Mz36HnMsYY Mickey Dufilho

More Related