Question 1

Which structure in the intrinsic cardiac conduction system is primarily responsible for initiating the electrical impulse that sets the pace of the heartbeat?

Accepted Answer

Sinoatrial (SA) node

Question 2

What is the main function of gap junctions in cardiac muscle cells?

Accepted Answer

To allow action potentials to pass rapidly from cell to cell

Question 3

If the 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

During the cardiac conduction pathway, which step immediately follows the action potential reaching the AV node?

Accepted Answer

100 ms delay

Question 6

Why does the AV node conduct impulses more slowly than the SA node?

Accepted Answer

To ensure the ventricles have enough time to fill with blood before they contract

Question 7

Which of the following best describes intrinsic conduction of the heart?

Accepted Answer

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

Question 8

Which structure is responsible for distributing the action potential from the atria to the ventricles?

Accepted Answer

Atrioventricular (AV) node

Question 9

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

Accepted Answer

Rhythmic generation of action potentials

Question 10

Which structure or structures are most directly responsible for allowing contraction of the ventricles to begin at the apex of the heart rather than in the septum closer to the AV node?

Accepted Answer

Purkinje fibers

Question 11

Which nervous system division increases heart rate by stimulating the SA node, AV node, and heart muscle?

Accepted Answer

Sympathetic nervous system

Question 12

If the sympathetic nerve fibers to the heart are severed, what would you expect to happen to the resting heart rate?

Accepted Answer

It would remain close to the intrinsic rate set by the SA node

Question 13

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

Accepted Answer

$$CO = HR 	imes SV$$

Question 14

A patient has a mutation that reduces the number of gap junctions in their cardiac muscle cells. What is the most likely effect on their heart function?

Accepted Answer

Slower spread of action potentials and possible arrhythmias

Question 15

Which step in the cardiac conduction pathway is responsible for the delay that allows the atria to contract before the ventricles?

Accepted Answer

Action potential reaches the AV node

Question 16

Which of the following is a direct effect of parasympathetic stimulation on the heart?

Accepted Answer

Decrease in heart rate

Question 17

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

Accepted Answer

SA node → AV node → AV bundle → bundle branches → Purkinje fibers → ventricular muscle cells

Question 18

Which of the following best explains why there are no gap junctions between cardiomyocytes of the atria and ventricles?

Accepted Answer

To prevent simultaneous contraction of atria and ventricles

Question 19

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

Accepted Answer

AV node

Question 20

Which of the following statements about the AV bundle (Bundle of His) is correct?

Accepted Answer

It transmits impulses from the AV node to the bundle branches

Cardiac Conduction System: Anatomy & Physiology Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards