PTX 475 Principles of Toxicology Final Exam Guide Q & A 2026 (Complete And Verified Study material) (34pages) LEARNEXAMS

1. What is the primary mechanism of action for organophosphate poisoning? A. Inhibition of cyclooxygenase B. Blockade of GABA receptors C. Inhibition of acetylcholinesterase D. Activation of nicotinic receptors Answer: C. Inhibition of acetylcholinesterase Rationale: Organophosphates exert their toxic effects primarily through the inhibition of acetylcholinesterase, leading to an accumulation of acetylcholine in the synapses. 2. Which principle of toxicology states that the toxicity of a substance is dependent on its concentration or dose? A. Principle of individual exposure B. Principle of dose-response C. Principle of cumulative risk D. Principle of threshold effect Answer: B. Principle of dose-respon