Nursing Elites

1. Which term refers to the ability of the heart to initiate impulses repetitively and spontaneously?

• A. Contractility
• B. Excitability
• C. Automaticity
• D. Rhythmicity

Correct answer: C

Rationale: The correct answer is C: Automaticity. Automaticity is the specific term used to describe the heart's ability to generate impulses repetitively and spontaneously. Contractility (A) refers to the ability of muscle fibers to contract, not the initiation of impulses. Excitability (B) is the ability of cells to respond to stimuli but is not specific to the heart's impulse generation. Rhythmicity (D) is a related term but does not specifically describe the heart's spontaneous impulse initiation.

2. What is the ability of cardiac cells to respond to an impulse by transmitting the impulse along cell membranes?

• A. Contractility
• B. Automaticity
• C. Conductivity
• D. Rhythmicity

Correct answer: C

Rationale: The correct answer is C, Conductivity. Conductivity refers to the ability of cardiac cells to transmit impulses along cell membranes. Contractility (Choice A) is the ability of cardiac cells to contract in response to an electrical stimulus, not transmit impulses. Automaticity (Choice B) is the ability of cardiac cells to spontaneously generate electrical impulses. Rhythmicity (Choice D) refers to the regular generation of electrical impulses by the heart's pacemaker cells, not the transmission of impulses along cell membranes.

3. What does the PR interval measure?

• A. Time it takes for the electrical impulse to travel from the atria to the ventricles
• B. Measurement of ventricular depolarization
• C. Duration of ventricular repolarization
• D. Segment representing the time between ventricular depolarization and repolarization

Correct answer: A

Rationale: The PR interval measures the time it takes for the electrical impulse to travel from the atria to the ventricles. It is crucial in diagnosing heart rhythm disorders, as abnormalities in this interval can indicate conduction abnormalities between the atria and ventricles. Choices B, C, and D are incorrect. The QRS complex represents ventricular depolarization, the QT interval represents the duration of ventricular repolarization, and the ST segment represents the time between ventricular depolarization and repolarization.

4. Which fibers distribute the electrical impulse to the ventricles, causing them to contract?

• A. Purkinje fibers
• B. SA node
• C. AV node
• D. Bundle of His

Correct answer: A

Rationale: The correct answer is Purkinje fibers. Purkinje fibers are specialized conducting fibers that distribute the electrical impulse to the ventricles, leading to their contraction. The SA node (sinoatrial node) is responsible for initiating the electrical impulse in the heart, the AV node (atrioventricular node) delays the impulse to allow for proper atrial contraction before ventricular contraction, and the Bundle of His transmits the impulse from the AV node to the ventricles. Therefore, choices B, C, and D are not the correct options for fibers directly distributing the impulse to the ventricles.

5. Which surgical procedure involves grafting a blood vessel to bypass a blocked artery in the heart?

• A. Coronary artery bypass graft (CABG)
• B. Valve replacement
• C. Stent placement
• D. Angioplasty

Correct answer: A

Rationale: The correct answer is A, Coronary artery bypass graft (CABG). This surgical procedure involves grafting a blood vessel to bypass a blocked coronary artery, improving blood flow to the heart muscle. Choice B, Valve replacement, is a procedure to replace a damaged heart valve and is not directly related to bypassing blocked arteries. Choice C, Stent placement, involves inserting a mesh tube to keep blocked arteries open and is different from grafting a blood vessel. Choice D, Angioplasty, is a procedure to widen narrowed or blocked arteries, typically using a balloon catheter, and does not involve grafting a blood vessel.

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