Question 1

Which part of the conduction system has a firing rate of 60 to 100?&#10;A) Purkinje fibers&#10;B) AV node&#10;C) SA node&#10;D) Bundle branches

Accepted Answer

The SA node, located in the right atrium of the heart, has a normal firing rate of 60 to 100 beats per minute and is often referred to as the "natural pacemaker" of the heart.

Question 2

Bachmann's bundle is located in the:&#10;A) top of right atrium.&#10;B) left atrium.&#10;C) left ventricle.&#10;D) right ventricle.

Accepted Answer

B

Question 3

The pacemaker that fires at 20 to 40 beats per minute is:&#10;A) Purkinje's network.&#10;B) the bundle of His.&#10;C) the AV node.&#10;D) the SA node.

Accepted Answer

The Purkinje fibers are part of the heart's conduction system and can act as a pacemaker with an intrinsic firing rate of 20 to 40 beats per minute when higher pacemakers fail.

Question 4

The bundle of His lies at the ________ of the interventricular septum.&#10;A) left&#10;B) bottom&#10;C) top&#10;D) right

Accepted Answer

The bundle of His is located at the top of the interventricular septum, where it conducts electrical impulses from the atrioventricular node to the ventricles.

Question 5

It is generally believed that a bit less than ________ of the cells are actual pacemaker cells.&#10;A) 25%&#10;B) 50%&#10;C) 75%&#10;D) 85%

Accepted Answer

About 50% of the cells in the sinoatrial (SA) node are pacemaker cells, which are responsible for generating the electrical signals that initiate each heartbeat. The other 50% of cells in the SA node are specialized conducting cells that help to spread the electrical signal throughout the heart.

Question 6

In the normal heart, this is the ONLY pathway between the atria and ventricles.&#10;A) AV node&#10;B) Left bundle branch&#10;C) Right bundle branch&#10;D) SA node

Accepted Answer

The AV node is the only pathway between the atria and ventricles in the normal heart. The SA node is responsible for initiating the electrical impulse that starts each heartbeat, but it is not the pathway between the atria and ventricles. The left and right bundle branches are part of the conduction system that spreads the electrical signal to the ventricles, but they are not the only pathway between the atria and ventricles.

Question 7

Nodes and bundles are located primarily beneath the:&#10;A) endocardium.&#10;B) myocardium.&#10;C) epicardium.&#10;D) pericardium.

Accepted Answer

The answer of Nodes and bundles are located primarily beneath...

Question 8

A(n) ________ pathway may be defined as an irregular muscle connection between the atria and the ventricles that bypasses the AV node.&#10;A) accessory&#10;B) Thorel's&#10;C) universal&#10;D) conductive

Accepted Answer

An accessory pathway, also known as an accessory conduction pathway, is a connection between the atria and the ventricles that bypasses the AV node. This pathway can cause a variety of heart rhythm disorders, including Wolff-Parkinson-White syndrome. Thorel's pathway and universal pathway are not commonly used terms in cardiac physiology. While conductive pathways exist in the heart, the term is too broad to specifically describe an accessory pathway.

Question 9

The SA node impulses result in:&#10;A) repolarization.&#10;B) depolarization.&#10;C) diastole.&#10;D) All of the above

Accepted Answer

The SA node impulses result in depolarization, causing the cardiac muscle cells to contract and creating a heartbeat. Repolarization occurs after depolarization, and diastole is the relaxation phase of the heart cycle. However, only depolarization is directly caused by the SA node impulses.

Question 10

The area where the internodal pathways join the bundle of His is:&#10;A) the right bundle branch.&#10;B) Purkinje's network.&#10;C) the left bundle branch.&#10;D) the AV junction.

Accepted Answer

The area where the internodal pathways join the bundle of His is referred to as the AV junction, which is where electrical impulses from the atria are relayed to the ventricles. Choice A, B, and C describe other parts of the electrical conduction system of the heart, but they do not specifically refer to the area where the internodal pathways connect to the bundle of His.

Question 11

If the vagus nerve is stimulated, the heart rate will:&#10;A) increase.&#10;B) decrease.

Accepted Answer

The answer of If the vagus nerve is stimulated, the...

Question 12

The bundle of His is also traditionally referred to as the ________ bundle.&#10;A) simple&#10;B) dedicated&#10;C) common&#10;D) universal

Accepted Answer

The answer of The bundle of His is also traditionally...

Question 13

The internodal tracts consist of anterior, middle, and posterior. They are also known as all of the following EXCEPT:&#10;A) Bachmann's bundle.&#10;B) Wenckebach's bundle.&#10;C) Thorel's pathway.&#10;D) Beasley's pathway.

Accepted Answer

The answer of The internodal tracts consist of anterior, middle,...

Question 14

The node that is located just above the tricuspid valve is the:&#10;A) central node.&#10;B) Purkinje node.&#10;C) SA node.&#10;D) AV node.

Accepted Answer

The answer of The node that is located just above...

Deck 4: The Electrical Conduction System