this is the inability of cardiac cells to respond to a new stimulus while it is still in contraction in response to a previous stimulus
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Nursing Elites

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Cardiovascular System Exam Questions

1. What is the term that describes the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus?

Correct answer: A

Rationale: Refractoriness is the correct term to describe the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus. This period is essential for the heart to complete its contraction and relaxation phases without interference. Excitability refers to the ability of cells to respond to stimuli, not the inability to respond. Contractility is the force of cardiac muscle contraction, and automaticity is the ability of cardiac cells to generate electrical impulses spontaneously, which are not relevant to the described scenario.

2. Which term refers to the contraction phase of the heart when blood is ejected from the chambers?

Correct answer: A

Rationale: The correct answer is A, systole. Systole is the phase of the cardiac cycle when the heart contracts and pumps blood out of the chambers. During diastole (choice B), the heart relaxes and fills with blood, contrasting with systole. Contractility (choice C) refers to the ability of the heart to contract effectively. Afterload (choice D) is the pressure the heart must work against to eject blood during systole.

3. The client on warfarin has an INR of 1.2. What is the nurse’s priority action?

Correct answer: A

Rationale: The correct answer is to increase the dose of warfarin. An INR of 1.2 is below the therapeutic range for a client on warfarin, indicating that the dose is subtherapeutic. The priority action in this situation is to adjust the dose to achieve the target therapeutic INR range (usually 2-3) to prevent thromboembolic events. Administering vitamin K is not necessary as the INR is low, and there are no signs of bleeding. Monitoring for signs of bleeding is important but not the priority in this case since the INR is subtherapeutic. Holding the next dose and notifying the healthcare provider would delay the intervention needed to adjust the dose and achieve the therapeutic range.

4. What is a life-threatening condition where the heart suddenly stops beating?

Correct answer: A

Rationale: Cardiac arrest is the correct answer. It is a sudden, unexpected loss of heart function, breathing, and consciousness, typically resulting in death if not treated immediately. Myocardial infarction (choice B) refers to a heart attack caused by a blockage in the coronary arteries. Heart failure (choice C) is a chronic condition where the heart is unable to pump blood efficiently. Atrial fibrillation (choice D) is an irregular and often rapid heart rate that can lead to complications but is not the same as cardiac arrest.

5. Which test measures how well the lungs work by assessing the amount of air the lungs can hold and how quickly air can be exhaled?

Correct answer: A

Rationale: The correct answer is A, Spirometry. Spirometry is a pulmonary function test that evaluates lung function by measuring the amount of air a person can exhale and how quickly, assisting in the diagnosis of conditions such as asthma and COPD. Choices B, C, and D are incorrect because Pulse oximetry measures oxygen saturation in the blood, Arterial blood gas (ABG) evaluates blood pH, oxygen, and carbon dioxide levels, and a Chest X-ray provides an image of the lungs but does not measure lung function.

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