Which of the following inhaled anesthetics can produce hepatic necrosis?

Correct Answer: C

Rationale: The correct answer is C: Halothane. Halothane can produce hepatic necrosis due to its metabolite, trifluoroacetic acid. This metabolite can lead to liver damage in susceptible individuals. Other choices, A (Sevoflurane), B (Desflurane), and D (Nitrous oxide) do not typically cause hepatic necrosis. Sevoflurane and Desflurane are not metabolized to toxic compounds that affect the liver, and Nitrous oxide is not known to cause hepatic necrosis. Therefore, the correct answer is C because of the specific hepatotoxic effects associated with Halothane.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Urokinase is a thrombolytic agent that activates plasminogen to plasmin, which dissolves blood clots. It does not inhibit Thromboxane A2. Thromboxane A2 is involved in platelet aggregation and vasoconstriction. Choices A, C, and D are incorrect because urokinase does not inhibit Thromboxane A2.

Correct Answer: A

Rationale: Verapamil is a calcium channel blocker that slows the influx of calcium ions in cardiac cells, leading to a decrease in automaticity in the SA node. This results in a decrease in heart rate. Therefore, choice A is correct. Choice B is incorrect because verapamil does affect automaticity. Choices C and D are incorrect as they do not accurately reflect the specific effect of verapamil on automaticity in the SA node.

Correct Answer: B

Rationale: Verapamil is a calcium channel blocker that slows down the heart rate by blocking L-type calcium channels. This action helps in reducing blood pressure and controlling heart rhythm. Therefore, statement B stating that verapamil increases heart rate is incorrect. Choices A, C, and D are true as verapamil blocks L-type calcium channels, relaxes coronary artery smooth muscle, and depresses cardiac contractility, respectively.

Correct Answer: D

Rationale: Step-by-step rationale for why choice D is correct: 1. Growth hormone stimulates the synthesis or release of somatomedins, supporting statement A. 2. Low levels of IGF-1 are associated with dwarfism, validating statement B. 3. Hypersecretion of growth hormone can lead to acromegaly, confirming statement C. 4. Choice D is incorrect because growth hormone is contraindicated in subjects with open epiphyses, not closed ones. This is because GH can stimulate bone growth, potentially causing issues in individuals with open growth plates.