Cardiovascular System

Question 1

Sinoatrial (SA) Node Location:

Answer 1

Located in the right atrium, near the opening of the superior vena cava.

Question 2

Sinoatrial (SA) Node Function:

Answer 2

The SA node is known as the natural pacemaker of the heart. It generates electrical impulses (action potentials) at a regular rate (around 60–100 beats per minute in a healthy adult).

Question 3

Sinoatrial (SA) Node Pathway:

Answer 3

The electrical impulse generated by the SA node spreads across both atria, causing them to contract. The impulse moves toward the atrioventricular (AV) node.

Question 4

Atrioventricular (AV) Node Location:

Answer 4

Situated at the junction between the atria and ventricles, near the interatrial septum.

Question 5

Atrioventricular (AV) Node Function:

Answer 5

The AV node delays the electrical impulse for approximately 0.1 seconds, allowing the atria to finish contracting and emptying blood into the ventricles before ventricular contraction begins. This delay is crucial for proper cardiac function.

Question 6

Atrioventricular (AV) Node Pathway

Answer 6

After the delay, the impulse passes from the AV node to the bundle of His.

Question 7

Bundle of His (Atrioventricular Bundle) Location:

Answer 7

The Bundle of His is located in the interventricular septum.

Question 8

Bundle of His (Atrioventricular Bundle) Function:

Answer 8

It conducts the electrical impulse from the AV node toward the ventricles. The Bundle of His is the only electrical connection between the atria and the ventricles since the fibrous skeleton of the heart prevents direct electrical conduction between these regions.

Question 9

Bundle of His (Atrioventricular Bundle) Pathway:

Answer 9

The impulse travels down the Bundle of His and divides into the right and left bundle branches.

Question 10

Right and Left Bundle Branches Location:

Answer 10

These branches run along the interventricular septum and extend toward the apex of the heart.

Question 11

Right and Left Bundle Branches Function:

Answer 11

The bundle branches conduct the impulse down toward the apex of the heart and toward the Purkinje fibers. The right bundle branch leads to the right ventricle, and the left bundle branch leads to the left ventricle

Question 12

Right and Left Bundle Branches Pathway

Answer 12

The impulse moves from the Bundle of His into these branches.

Question 13

Purkinje Fibers Location:

Answer 13

The Purkinje fibers are located throughout the myocardium of the ventricles, particularly in the inner walls of the ventricles

Question 14

Purkinje Fibers Function

Answer 14

The Purkinje fibers rapidly distribute the electrical impulse throughout the ventricles, causing them to contract in a coordinated manner. This ensures that the contraction starts at the apex and moves upwards, efficiently pumping blood into the pulmonary artery and aorta.

Question 15

Purkinje Fibers Pathway:

Answer 15

The electrical impulse spreads from the bundle branches to the Purkinje fibers, causing ventricular contraction

Question 16

Ventricular Muscle Cells Function:

Answer 16

The electrical impulses cause the ventricular muscle cells to depolarize, leading to the contraction of the ventricles, which pumps blood to the lungs (right ventricle) and the rest of the body (left ventricle).