Cardiovascular System Exam

Correct Answer: A

Rationale: The correct answer is A: Pulmonary toxicity. Amiodarone is known for causing serious pulmonary toxicity, which can be fatal. Monitoring for pulmonary toxicity is crucial due to its potential severity. Choice B, thyroid dysfunction, is a common side effect of amiodarone but is not as immediately life-threatening as pulmonary toxicity. Choices C and D, liver toxicity and renal dysfunction, are potential side effects of amiodarone but are not as critical or as common as pulmonary toxicity, making them less important to monitor initially.

Correct Answer: A

Rationale: Excitability is the correct term that describes the ability of cardiac cells to respond to an impulse by contracting. Excitability refers to the cell's ability to respond to stimuli and generate an action potential. Choice B, Contractility, is incorrect as it refers to the ability of cardiac cells to contract after receiving a stimulus, not the response to the impulse itself. Choice C, Rhythmicity, is incorrect as it pertains to the heart's ability to contract rhythmically without external stimulation. Choice D, Conductivity, is incorrect as it refers to the ability of cardiac cells to transmit an impulse from cell to cell, not the direct response to the impulse by contracting.

Correct Answer: A

Rationale: Atherosclerosis is the correct answer. It is a condition characterized by the hardening and narrowing of arteries supplying blood to the heart due to plaque buildup. This condition increases the risk of heart attacks. Choice B, aneurysm, refers to a balloon-like bulge in an artery, not the hardening and narrowing of arteries. Choice C, arrhythmia, is an irregular heartbeat and not related to arterial hardening. Choice D, peripheral artery disease, involves the narrowing of arteries that supply blood to the limbs, not specifically to the heart.

Correct Answer: A

Rationale: The correct answer is A: Contractility. Contractility specifically refers to the change in the force of contraction of the heart muscle without changing its length. In this scenario, the focus is on the change in the inotropic state of the muscle, which directly relates to contractility. Choice B, Excitability, refers to the ability of a cell to respond to a stimulus, not specifically related to changes in contractile force. Choice C, Refractoriness, pertains to the period during which a cell is unresponsive to a new stimulus. Choice D, Automaticity, refers to the ability of cardiac cells to spontaneously generate electrical impulses.

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.