Cardiovascular System Exam Questions

Correct Answer: A

Rationale: Refractoriness is the correct term to describe the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus. This period is essential for the heart to complete its contraction and relaxation phases without interference. Excitability refers to the ability of cells to respond to stimuli, not the inability to respond. Contractility is the force of cardiac muscle contraction, and automaticity is the ability of cardiac cells to generate electrical impulses spontaneously, which are not relevant to the described scenario.

Correct Answer: A

Rationale: The correct answer is A: Coronary artery bypass graft (CABG). CABG involves grafting a blood vessel to bypass a blocked coronary artery, enhancing blood flow to the heart muscle. This procedure helps reduce the risk of heart attack by restoring proper blood circulation to the heart. Choice B, valve replacement, is a different surgical procedure that involves replacing damaged or dysfunctional heart valves. Choice C, angioplasty, is a minimally invasive procedure that uses a balloon to open narrowed or blocked blood vessels. Choice D, endarterectomy, is the surgical removal of plaque from the lining of an artery to improve blood flow.

Correct Answer: A

Rationale: Tachycardia is the correct answer because it is a condition characterized by a fast heart rate, which can decrease the heart's efficiency in pumping blood. Bradycardia, on the other hand, refers to a slow heart rate, which is the opposite of what is described in the question. Arrhythmia is a general term for any irregularity in the heart's rhythm, not necessarily specifically related to a fast heart rate. Ventricular fibrillation is a life-threatening arrhythmia where the heart's lower chambers quiver instead of pumping blood effectively, but it is not specifically characterized by a fast heart rate.

Correct Answer: A

Rationale: Dilated cardiomyopathy is characterized by the weakening and enlargement of the heart muscle, leading to its reduced ability to pump blood effectively. This condition is different from hypertrophic cardiomyopathy, which involves abnormal thickening of the heart muscle, myocarditis, which is inflammation of the heart muscle, and pericarditis, which is inflammation of the pericardium. Therefore, the correct answer is Dilated cardiomyopathy.

Correct Answer: A

Rationale: The correct answer is A: Heart failure. Heart failure occurs when the heart is unable to pump blood effectively, resulting in a buildup of fluid in the lungs and other parts of the body. Choice B, Cardiomyopathy, refers to diseases of the heart muscle, not specifically the inability to pump blood effectively. Choice C, Myocardial infarction, is a heart attack caused by a blocked blood supply to the heart muscle, not directly related to the heart's pumping efficiency. Choice D, Pulmonary edema, is a condition characterized by fluid accumulation in the lungs, often a consequence of heart failure but not the primary condition described in the question.