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 individuals sinoatrial node ceases to function.
b. the individuals central nervous system fails to signal the heart to contract and relax.
c. the individuals arteries are blocked.
d. the valves in the individuals heart cease to function.

Explanation:

• Option A: The sinoatrial (SA) node is the natural pacemaker of the heart, generating electrical impulses to regulate heartbeats. If it ceases to function, an artificial pacemaker can take over by sending electrical impulses to contract the heart muscles and regulate the heartbeat.
• Option B: The central nervous system (CNS) is not the primary regulator of the heart's intrinsic electrical rhythm for contraction/relaxation. The heart has its own intrinsic conduction system (SA node, AV node, etc.). A pacemaker does not address CNS signaling issues for the heart.
• Option C: Blocked arteries are a problem related to blood flow due to plaque or clots, not the heart's electrical rhythm or contraction regulation. A pacemaker does not treat blocked arteries (treatments like stents, bypass, or medications for cholesterol would be more relevant).
• Option D: Heart valves function to prevent backflow of blood, and their malfunction (e.g., stenosis, regurgitation) is a structural/mechanical issue, not related to the heart's electrical pacing. A pacemaker cannot correct valve function.

Answer:

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