Question

select the correct answer.

pacemakers maintain the heartbeat in people who suffer from certain defects. the function of an artificial pacemaker is to send electrical impulses that will contract the heart muscles and regulate the pumping of the heart. which condition could be corrected by a pacemaker?

a. the individual’s sinoatrial node ceases to function.

b. the individual’s central nervous system fails to signal the heart to contract and relax.

c. the individual’s arteries are blocked.

d. the valves in the individual’s heart cease to function.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: The sinoatrial (SA) node is the natural pacemaker of the heart, generating electrical impulses to regulate heartbeat. If it ceases to function, an artificial pacemaker can take over by sending electrical impulses to contract the heart muscles and regulate pumping, so this is a condition a pacemaker can correct.
• Option B: The central nervous system (CNS) is not the primary regulator of the heart's intrinsic rhythm. The heart has its own electrical conduction system (like the SA node). A pacemaker addresses issues with the heart's internal electrical signaling, not CNS - related signaling failures.
• Option C: Blocked arteries are a problem related to blood flow and vessel obstruction, not the electrical regulation of the heart's beating, so a pacemaker cannot correct this.
• Option D: Heart valves are responsible for preventing backflow of blood, not for the electrical impulses that control heart muscle contraction. A pacemaker does not address valve - related issues.

Answer:

A. The individual’s sinoatrial node ceases to function.