1. Intrinsic Conduction System
P1-3

2. Intrinsic Conduction System (ICS)
Sets the basic rhythm of the beating heart
Consists of autorhythmic cardiac cells
Initiate & distribute impulses (action potentials) t/o heart
Brain only regulates how fast or slow

3. Nodal Cells & Other Structures
Sinoatrial (SA) Node
Internodal Pathway
Atrioventricular (AV) Node
Atrioventricular (AV) Bundle (Bundle of His)
Bundle Branches
Purkinje Fibers
Sinoatrial (SA) Node – upper RA; pacemaker; initiates depol impulse; AP spreads t/ atria to AV node; sets overall pace of heartbeat
Internodal Pathway – walls of atria; links SA node to AV node; distributes AP to contractile cells of atria
Atrioventricular (AV) Node – inf interatrial septrum; AP delayed while atria contract, then transmitted to AV bundle (BoH)
Atrioventricular (AV) Bundle (Bundle of His) – only electrical connection b/w atria & ventricles; AP from IAS to IVS; connects AV node to bundle branches
Bundle Branches – convey AP down IVS
Purkinje Fibers – lower IVS to apex of heart, continues sup t/ myocardium of ventricles; convey AP to contractile cells of ventricles

4. YouTube CrashCourse Video