Nursing Elites

1. Which valve opens during ventricular systole and closes during ventricular diastole?

• A. Aortic valve
• B. Pulmonary valve
• C. Mitral valve
• D. Tricuspid valve

Correct answer: B

Rationale: The correct answer is B: Pulmonary valve. The pulmonary valve opens during ventricular systole to allow blood to flow from the right ventricle into the pulmonary artery. The aortic valve opens during ventricular systole to allow blood to flow from the left ventricle into the aorta. The mitral valve and tricuspid valve are atrioventricular valves that open during ventricular diastole to allow blood to flow from the atria into the ventricles.

2. What term refers to the degree of myocardial fiber stretch before contraction, related to the volume of blood distending the ventricles at the end of diastole, and determined by the amount of venous return?

• A. Preload
• B. Afterload
• C. Contractility
• D. Ejection fraction

Correct answer: A

Rationale: The correct answer is A: Preload. Preload is the degree of myocardial fiber stretch before contraction, influenced by the volume of blood returning to the heart. This parameter is related to the amount of blood in the ventricles at the end of diastole. Choice B, Afterload, refers to the pressure or resistance that the ventricles must overcome to eject blood. Choice C, Contractility, is the intrinsic ability of the heart muscle to contract. Choice D, Ejection fraction, is the percentage of blood pumped out of the ventricles with each contraction.

3. Which valve prevents backflow of blood into the right ventricle from the pulmonary artery?

• A. Pulmonary valve
• B. Aortic valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: A

Rationale: The correct answer is the Pulmonary valve. The Pulmonary valve prevents backflow of blood into the right ventricle from the pulmonary artery after it has been ejected. The Aortic valve (choice B) prevents backflow from the aorta into the left ventricle. The Tricuspid valve (choice C) prevents backflow of blood into the right atrium from the right ventricle. The Mitral valve (choice D) prevents backflow from the left ventricle into the left atrium.

4. What is the approximate stroke volume of the heart?

• A. Approximately 60 mL of blood per beat
• B. Approximately 70 mL of blood per beat
• C. Approximately 80 mL of blood per beat
• D. Approximately 90 mL of blood per beat

Correct answer: B

Rationale: The correct answer is B: Approximately 70 mL of blood per beat. The stroke volume of the heart is typically around 70 mL, indicating the volume of blood ejected from the left ventricle with each contraction. Choices A, C, and D are incorrect as they do not represent the standard approximate stroke volume of the heart, which is around 70 mL per beat.

5. 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.

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