ATI RN
Cardiovascular System Exam
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. Which of the following is a type of heart valve disease where the aortic valve becomes narrowed, restricting blood flow from the heart to the rest of the body?
- A. Aortic stenosis
- B. Mitral stenosis
- C. Tricuspid regurgitation
- D. Pulmonary hypertension
Correct answer: A
Rationale: The correct answer is Aortic stenosis. In aortic stenosis, the aortic valve becomes narrowed, which obstructs the blood flow from the heart to the rest of the body. This condition can lead to symptoms like chest pain, shortness of breath, and fainting. Mitral stenosis (choice B) involves narrowing of the mitral valve, not the aortic valve. Tricuspid regurgitation (choice C) is a condition where the tricuspid valve leaks, causing blood to flow backward in the heart. Pulmonary hypertension (choice D) is high blood pressure in the arteries of the lungs.
3. Which structure serves as the normal pacemaker of the heart?
- A. SA node
- B. AV node
- C. Purkinje fibers
- D. Atria
Correct answer: A
Rationale: The correct answer is the SA node. The sinoatrial (SA) node is known as the natural pacemaker of the heart as it generates electrical impulses initiating each heartbeat. The SA node is located in the right atrium and sets the rhythm and rate of the heartbeat. The AV node (choice B) is responsible for delaying the electrical impulse to allow the atria to contract before the ventricles. Purkinje fibers (choice C) are specialized cardiac fibers responsible for the rapid conduction of impulses to the myocardial cells, and the atria (choice D) are the upper chambers of the heart involved in receiving blood from the veins.
4. Which condition occurs when the heart muscle is damaged due to a lack of oxygen, often resulting from a heart attack?
- A. Myocardial infarction
- B. Angina
- C. Pericarditis
- D. Pulmonary embolism
Correct answer: A
Rationale: The correct answer is A: Myocardial infarction. Myocardial infarction, commonly known as a heart attack, is the condition where the heart muscle is damaged due to a lack of oxygen, typically caused by a blocked coronary artery. Angina (choice B) is chest pain or discomfort that occurs when the heart muscle doesn't receive enough oxygen-rich blood. Pericarditis (choice C) is the inflammation of the pericardium, the thin sac-like membrane surrounding the heart. Pulmonary embolism (choice D) is a blockage in one of the pulmonary arteries in the lungs, often caused by a blood clot.
5. What test measures the electrical activity of the heart over a period of time, typically 24 to 48 hours?
- A. Holter monitor
- B. Echocardiogram
- C. Stress test
- D. Arterial blood gas (ABG)
Correct answer: A
Rationale: The correct answer is A, Holter monitor. A Holter monitor is a portable device that records the electrical activity of the heart over a period of 24 to 48 hours. It is used to detect arrhythmias and other heart conditions. Choice B, Echocardiogram, is a test that uses sound waves to create images of the heart's structure and function, not focused on the electrical activity. Choice C, Stress test, evaluates the heart's function under stress but does not monitor electrical activity over an extended period. Choice D, Arterial blood gas (ABG), measures the levels of oxygen and carbon dioxide in the blood, unrelated to measuring the electrical activity of the heart over time.
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