Cardiovascular System Exam

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 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 correct answer is A: Platelet count. When administering enoxaparin (Lovenox), it is crucial to monitor the platelet count because enoxaparin can cause a rare but serious side effect known as heparin-induced thrombocytopenia, which is a decrease in platelet count that can lead to increased risk of bleeding. Monitoring the platelet count allows for early detection of this potential complication. Choices B, C, and D are incorrect because aPTT, Hemoglobin, and INR are not the most important lab values to monitor specifically when administering enoxaparin.

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: B

Rationale: The correct answer is B: Atrioventricular Valves. The atrioventricular (AV) valves, including the mitral valve and tricuspid valve, close during ventricular systole to prevent backflow of blood from the ventricles into the atria. They open during ventricular diastole to allow blood flow from the atria into the ventricles. Semilunar valves, choice A, are located at the exits of the ventricles and prevent backflow into the ventricles. The mitral valve and tricuspid valve, choices C and D, are specific types of AV valves.