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

Accepted Answer

Atrioventricular (AV) node

Question 4

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 5

During the cardiac conduction pathway, which structure is responsible for the delay that allows the atria to contract before the ventricles?

Accepted Answer

Atrioventricular (AV) node

Question 6

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

Accepted Answer

Sinoatrial node: left atrium

Question 7

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

Accepted Answer

Rhythmic generation of action potentials.

Question 8

Which of the following best explains why the AV node conducts impulses more slowly than other parts of the conduction system?

Accepted Answer

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

Question 9

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 10

Which of the following best describes the effect of increased sympathetic nervous system activity on heart rate?

Accepted Answer

It increases heart rate by stimulating the SA and AV nodes.

Question 11

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

Accepted Answer

The ability of the ventricles to contract efficiently

Question 12

Which of the following is the correct sequence of electrical conduction in the heart?

Accepted Answer

SA node → AV node → AV bundle (Bundle of His) → Bundle branches → Purkinje fibers

Question 13

Which of the following statements about the intrinsic cardiac conduction system is TRUE?

Accepted Answer

It is composed of specialized cardiac cells that can generate and conduct action potentials.

Question 14

A drug that blocks gap junctions in the heart would most likely have which of the following effects?

Accepted Answer

Prevent the spread of action potentials between cardiac muscle cells

Question 15

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

Accepted Answer

To keep contractions coordinated and prevent simultaneous contraction of atria and ventricles

Question 16

Which of the following would most likely occur if the parasympathetic nervous system to the heart was severed?

Accepted Answer

Resting heart rate would increase

Question 17

Which of the following is a direct effect of the AV bundle (Bundle of His) in the cardiac conduction system?

Accepted Answer

Conducts the action potential from the AV node to the bundle branches

Question 18

A patient’s ECG shows that the ventricles are contracting before the atria have finished contracting. Which part of the conduction system is most likely malfunctioning?

Accepted Answer

AV node

Question 19

Which of the following best describes the role of the medulla oblongata in heart rate control?

Accepted Answer

It is responsible for chronotropic control of heart rate via autonomic nervous system pathways.

Question 20

Which of the following best explains why the heart can continue to beat even when removed from the body and placed in a nutrient solution?

Accepted Answer

The intrinsic conduction system allows the heart to generate its own action potentials.

Cardiac Conduction System and Control of Heart Rate: Structured Study Notes

Study Guide - Practice Questions

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