Electrical Conduction System

Question 1

Sinoatrial (SA) Node

Answer 1

Generates impulse in heart
“Pacemaker”
Located in R atrium
60-100 bpm

Question 2

Internodal Pathways

Answer 2

Connection between SA and AV nodes
Located in walls of atria
Aid in conduction of impulses through different parts of heart

Question 3

Atrioventricular (AV) Node

Answer 3

Located at center of heart btwn atria and ventricles
Slows conduction rate of impulses prior to reaching ventricles
Delay ensures smooth cardiac cycle
Allows atria to completely eject blood prior to ventricle contraction

Question 4

Bundle of His

Answer 4

Heart muscle fibers in inferior interatrial septum

Transmit impulses from AV node to L/R bundle branches

Question 5

L Bundle Branch

Answer 5

Muscle fibers lead impulses to L ventricle

Initiate L ventricle contraction

Question 6

R Bundle Branch

Answer 6

Muscle fibers lead impulses to R ventricle

Initiate R ventricle contraction

Question 7

Purkinje System

Answer 7

Located wi ventricular walls
Quickly conduct cardiac activity
Cause synchronized contraction of ventricles

Question 8

Depolarization

Answer 8

Electrical charge altered due to changes in electrolytes

Charged effect causes muscles to contract & enables depolarization

Question 9

Repolarization

Answer 9

Chemical pumps in cells reestablish negative charge

Neutralizes excess electrolytes making muscles return to resting state