Chapter 4 - The Electrical Conduction System

The pacemaker that fires at 20 to 40 beats per minute is:

• The AV node

• The bundle of His

• The SA node

• Purkinje's network

If the vagus nerve is stimulated, the heart rate will:

• Decrease

• Increase

It is generally believed that a bit less than ______ of the cells are actual pacemaker cells.

• 50%

• 75%

• 85%

• 25%

The SA node impulses result in:

• Repolarization

• Diastole

• Depolarization

• All of the above

Bachmann's bundle is located in the:

• Left atrium

• Left ventricle

• Top of right atrium

• Right ventricle

The internodal tracts consist of anterior, middle, and posterior. They are also known as all of the following EXCEPT:

• Thorel's pathway

• Wenckebach's bundle

• Beasley's pathway

• Bachmann's bundle

A(n) _________ pathway may be defined as an irregular muscle connection between the atria and the ventricles that bypasses the AV node.

• Universal

• Conductive

• Accessory

• Thorel's

The bundle of His lies at the ____________ of the interventricular septum.

• Right

• Top

• Bottom

• Left

Which part of the conduction system has a firing rate of 60 to 100?

• Bundle branches

• Purkinje fibers

• SA node

• AV node

Nodes and bundles are located primarily beneath the:

• Pericardium

• Myocardium

• Epicardium

• Endocardium