Conduction System

Question 0

Internodal tracts

Answer 0

How electrical impulses spread from the SA node to the AV node

Question 1

SA node

Answer 1

Located in the right atrium at the junction of the superior vena cava and right atrium
Generates an electrical impulse 60-100 times per min
Considered the pacemaker of the heart

Question 2

AV node

Answer 2

Sits in the floor of the right atrium near the junction of the inter-atrial and interventricular septae
Slows conduction of the electrical impulse to allow time for the atria to contract and fill the ventricles with blood

Question 3

Bundle of His

Answer 3

Arises from the inferior portion of the AV node and passes through the interventricular septum

Question 4

AV junction

Answer 4

Consists of the atrial approaches to the AV node, the AV node, and the common branch of the Bundle of His
Pacemaker cells located within generate impulses at a rate of 40-60 times per min

Question 5

Bundle Branches

Answer 5

Travel down the interventricular septum to the right and left ventricles
Conduct the impulses rapidly through the ventricles to the Purkinje cells

Question 6

Purkinje Network

Answer 6

Network of fibers arising from the terminal ends of the bundle branches
Distributed throughout the ventricular muscle
Conduct the electrical impulse to the mechanical cells of the myocardium
Contain pacemaker cells which can generate impulses at an inherent rate less than 40 times per min

Question 7

Positive deflection

Answer 7

Created when an electrical impulse moves through the heart toward the positive electrode
Upright line

Question 8

Negative deflection

Answer 8

Created when an electrical impulse moves away from the positive electrode
Downward line

Question 9

Most common lead used for monitoring and it’s placement

Answer 9

Lead II- positive electrode placed over the apex of the heart (4th- 5th intercostal space, left midclavicular line) while the negative electrode is placed beneath the clavicle to the right of the sternum