Question 1

Which structure in the intrinsic cardiac conduction system is primarily responsible for initiating the heartbeat by generating action potentials at regular intervals?

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 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

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

Accepted Answer

100 ms delay

Question 6

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

Accepted Answer

It allows the atria to contract before the ventricles

Question 7

Which of the following best describes the 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 throughout the ventricles, leading to their contraction?

Accepted Answer

Purkinje fibers

Question 9

The sympathetic nervous system affects heart rate by:

Accepted Answer

Increasing heart rate by stimulating the SA node

Question 10

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

Accepted Answer

$CO = HR 	imes SV$

Question 11

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

Accepted Answer

The ventricles would contract less efficiently

Question 12

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 13

If the parasympathetic nervous system is severed, what would be the expected effect on resting heart rate?

Accepted Answer

Resting heart rate would increase

Question 14

Which of the following structures is found in the interventricular septum and is responsible for transmitting impulses to the right and left bundle branches?

Accepted Answer

Atrioventricular (AV) bundle (Bundle of His)

Question 15

Which of the following is the correct sequence for the spread of action potentials in the heart?

Accepted Answer

SA node → AV node → AV bundle → bundle branches → Purkinje fibers → contractile cells

Question 16

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 17

Which of the following best explains why the AV node has fewer gap junctions than the SA node?

Accepted Answer

It ensures the ventricles have enough time to fill with blood before they contract

Question 18

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

Accepted Answer

Increased heart rate

Question 19

Which of the following is the primary function of the pacemaker cells in the SA node?

Accepted Answer

Rhythmic generation of action potentials

Question 20

A patient is experiencing bradycardia (slow heart rate). Which part of the conduction system is most likely malfunctioning?

Accepted Answer

Sinoatrial (SA) node

Cardiac Conduction System: Anatomy & Physiology Study Notes part A

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