Intrinsic Conduction System

Question 1

Composition

Answer 1

• special tissue (mix of muscle and nervous (nodes))
• sinoatrial (SA) node (R atrium)
• AV node (junction of R atrium and ventricle)
• AV bundle (bundle of His) (branch out into the interventricular septum)
• Purkinje fibers (muscles of ventricular wall)

Question 2

Function

Answer 2

-to allow muscles to have different rhythms in different areas consistently (atrial 60bts/min, ventricles 20~40bts/min)

Question 3

SA node

Answer 3

• pacemaker, starts each heartbeat
• highest rate of depolarization
• impulse spreads through the atria to the AV node

Question 4

AV node

Answer 4

• impulse delayed briefly to let the atria finish contracting
• then impulse quickly goes through AV bundles and Purkinje fibers, causing the wringing contractions of ventricles, starting at the apex, moving up