Cardiovascular System Exam

Correct Answer: A

Rationale: The correct answer is A: Coronary artery bypass graft (CABG). This surgical procedure is used to redirect blood flow around a blocked or narrowed artery by using a graft from another part of the body. Choices B, C, and D are incorrect because valve replacement involves replacing heart valves, aneurysm repair addresses the treatment of aneurysms, and atherectomy is a procedure to remove plaque from blood vessels, none of which match the description provided in the question.

Correct Answer: A

Rationale: Mitral regurgitation is the correct answer. It occurs when the mitral valve does not close properly, allowing blood to flow backward into the left atrium. This condition can lead to symptoms such as fatigue, shortness of breath, and if left untreated, it can progress to heart failure. Aortic stenosis (choice B) is a different heart valve condition characterized by narrowing of the aortic valve, restricting blood flow from the heart. Tricuspid regurgitation (choice C) involves the tricuspid valve not closing properly, leading to blood flowing back into the right atrium. Pulmonary hypertension (choice D) is a condition characterized by high blood pressure in the arteries of the lungs.

Correct Answer: A

Rationale: The PR interval measures the time it takes for the electrical impulse to travel from the atria to the ventricles. It is crucial in diagnosing heart rhythm disorders, as abnormalities in this interval can indicate conduction abnormalities between the atria and ventricles. Choices B, C, and D are incorrect. The QRS complex represents ventricular depolarization, the QT interval represents the duration of ventricular repolarization, and the ST segment represents the time between ventricular depolarization and repolarization.

Correct Answer: A

Rationale: Mitral regurgitation is the condition where the heart's mitral valve does not close properly, allowing blood to leak backward into the left atrium. This can result in symptoms like shortness of breath and fatigue. Choices B, C, and D are incorrect because aortic stenosis, tricuspid regurgitation, and pulmonary hypertension involve different heart valves or conditions, not the mitral valve specifically.

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.