this is the ability of cardiac cells to generate an electrical impulse without being stimulated by an external source
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Nursing Elites

ATI RN

Cardiovascular System Exam

1. What is the ability of cardiac cells to generate an electrical impulse without being stimulated by an external source?

Correct answer: A

Rationale: Automaticity is the correct answer because it refers to the inherent ability of cardiac cells to generate electrical impulses without the need for external stimulation. Contractility (Choice B) is the ability of the heart muscle to contract and generate force, not related to electrical impulse generation. Conductivity (Choice C) refers to the ability of cardiac cells to transmit electrical impulses from cell to cell, not the spontaneous generation of impulses. Refractoriness (Choice D) is the period during which the cardiac cells are recovering and not able to respond to a new stimulus, not the spontaneous generation of impulses.

2. What is the term for the amount of blood ejected by the left ventricle into the aorta per beat, determined by preload, contractility, and afterload?

Correct answer: A

Rationale: The correct answer is A: Stroke volume. Stroke volume refers to the volume of blood ejected by the left ventricle during each heartbeat. This is determined by preload (the degree of stretch of the cardiac muscle fibers at the end of diastole), contractility (the force of myocardial contraction), and afterload (the pressure or resistance that the ventricle must overcome to eject blood). Choice B, Cardiac output, is the volume of blood pumped by the heart per minute and is calculated by multiplying the heart rate by the stroke volume. Choice C, End-diastolic volume, is the volume of blood in the ventricle at the end of diastole before contraction. Choice D, Ejection fraction, is the proportion of blood pumped out of the ventricle with each contraction, calculated by dividing the stroke volume by the end-diastolic volume.

3. What is a condition where the heart beats with an irregular or abnormal rhythm?

Correct answer: A

Rationale: Arrhythmia is the correct answer because it refers to an irregular or abnormal heart rhythm, which can cause the heart to beat too fast, too slow, or erratically. Hypertension (choice B) is high blood pressure and not directly related to irregular heart rhythm. Tachycardia (choice C) is a condition where the heart beats too quickly, not necessarily irregularly. Bradycardia (choice D) is a condition where the heart beats too slowly, not necessarily irregularly. Therefore, only arrhythmia (choice A) fits the description provided in the question.

4. The client on spironolactone (Aldactone) has a potassium level of 5.6 mEq/L. What is the nurse’s priority action?

Correct answer: A

Rationale: The correct answer is A: Hold the spironolactone and notify the healthcare provider. A potassium level of 5.6 mEq/L is high, indicating hyperkalemia. Spironolactone is a potassium-sparing diuretic that can further elevate potassium levels. Therefore, the priority action is to withhold the medication to prevent exacerbating hyperkalemia and notify the healthcare provider for further management. Option B is incorrect because administering potassium supplements would worsen the hyperkalemia. Option C is incorrect as continuing spironolactone can lead to a further increase in potassium levels. Option D is incorrect as increasing the dose of spironolactone would be inappropriate in the presence of elevated potassium levels.

5. Which medication relaxes the muscles around the airways, making it easier to breathe?

Correct answer: A

Rationale: The correct answer is A, Bronchodilator. Bronchodilators are medications that relax the muscles surrounding the airways, which helps to open them and makes breathing easier. Corticosteroids (choice B) work by reducing inflammation, antihistamines (choice C) are used to manage allergies, and mucolytics (choice D) help to break down and thin mucus in the airways.

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