Nursing Elites

1. 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.

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?

• A. Stroke volume
• B. Cardiac output
• C. End-diastolic volume
• D. Ejection fraction

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 are the pressure-sensitive structures located in the aortic and carotid bodies called?

• A. Baroreceptors
• B. Chemoreceptors
• C. Nociceptors
• D. Mechanoreceptors

Correct answer: A

Rationale: Baroreceptors are the correct answer. Baroreceptors are specialized sensory receptors that detect changes in pressure within blood vessels. They are primarily located in the aortic arch and carotid sinuses, where they play a crucial role in regulating blood pressure. Chemoreceptors (Choice B) are receptors that detect chemical changes, not pressure changes. Nociceptors (Choice C) are responsible for detecting painful stimuli. Mechanoreceptors (Choice D) respond to mechanical stimuli such as touch, pressure, and vibration, but they are not specifically located in the aortic and carotid bodies.

4. The nurse is administering a calcium channel blocker. What is the primary effect of this medication on the cardiovascular system?

• A. Decreases heart rate
• B. Increases heart rate
• C. Increases blood pressure
• D. Decreases blood pressure

Correct answer: D

Rationale: The correct answer is D: Decreases blood pressure. Calcium channel blockers primarily work by relaxing the blood vessels, leading to a decrease in blood pressure. Choice A, 'Decreases heart rate,' is incorrect because calcium channel blockers do not significantly affect heart rate. Choice B, 'Increases heart rate,' is incorrect as calcium channel blockers do not have a primary effect of increasing heart rate. Choice C, 'Increases blood pressure,' is incorrect as the primary effect of calcium channel blockers is to decrease blood pressure by vasodilation.

5. Which term refers to a condition where the blood supply to part of the heart muscle is blocked, often referred to as a heart attack?

• A. Myocardial infarction
• B. Arrhythmia
• C. Stroke
• D. Aneurysm

Correct answer: A

Rationale: The correct answer is A, myocardial infarction. A myocardial infarction, commonly known as a heart attack, occurs when the blood supply to part of the heart muscle is blocked, often by a blood clot. Choices B, C, and D are incorrect because arrhythmia refers to an irregular heartbeat, stroke involves the interruption of blood flow to the brain, and an aneurysm is a bulge in a blood vessel.

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