Question 1

Which structure in the cardiac conduction system is primarily responsible for initiating the electrical impulse that sets the heart's rhythm?

Accepted Answer

Sinoatrial (SA) node

Question 2

The rapid spread of action potentials through the heart is facilitated by which of the following features?

Accepted Answer

Gap junctions

Question 3

If the sinoatrial (SA) node fails to function, which part of the conduction system is most likely to take over as the pacemaker?

Accepted Answer

Atrioventricular (AV) node

Question 4

Which of the following correctly matches the cardiac conduction structure to its location in the heart?

Accepted Answer

Sinoatrial node: left atrium

Question 5

What is the primary function of the pacemaker cells in the SA node?

Accepted Answer

Rhythmic generation of action potentials

Question 6

Which statement best describes intrinsic conduction of the heart?

Accepted Answer

Cells within the heart can initiate and transmit action potentials without nervous system input.

Question 7

During the cardiac conduction pathway, which step occurs immediately after the action potential reaches the AV node?

Accepted Answer

100 ms delay

Question 8

Why does the AV node conduct impulses more slowly than other parts of the conduction system?

Accepted Answer

It has fewer gap junctions

Question 9

Which structure is most directly responsible for allowing contraction of the ventricles to begin at the apex of the heart?

Accepted Answer

Purkinje fibers

Question 10

Which of the following best explains how the slower conduction through the AV node benefits heart function?

Accepted Answer

Ensures that the ventricles have enough time to fill with blood before they contract.

Question 11

Which equation best represents the relationship between heart rate ($$HR$$), cardiac output ($$CO$$), and stroke volume ($$SV$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 12

If the sympathetic nervous system is activated, what is the expected effect on heart rate?

Accepted Answer

Heart rate increases

Question 13

Which pathway correctly describes the sequence of electrical conduction in the heart?

Accepted Answer

SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers

Question 14

A patient has damage to the Purkinje fibers. Which of the following is most likely to occur?

Accepted Answer

Ventricular contraction will be delayed or uncoordinated.

Question 15

Which of the following is NOT a function of the cardiac conduction system?

Accepted Answer

Regulating blood pressure directly

Question 16

If the parasympathetic nervous system is severed, what would happen to the resting heart rate?

Accepted Answer

Resting heart rate would increase

Question 17

Which of the following best describes the role of conducting fibers in the heart?

Accepted Answer

They transmit action potentials rapidly to specific regions.

Question 18

Which part of the cardiac conduction system is located in the interventricular septum?

Accepted Answer

Bundle branches

Question 19

Which of the following statements about gap junctions in cardiac muscle is correct?

Accepted Answer

They allow ions and action potentials to pass directly from cell to cell.

Question 20

A patient’s ECG shows a delay between atrial and ventricular contraction. Which part of the conduction system is most likely affected?

Accepted Answer

Atrioventricular (AV) node

Cardiac Conduction System and Control of Heart Rate

Study Guide - Practice Questions