Difficulty: Medium
Average Score: 78%
Simulated
A student asks the pharmacology instructor to explain the action of anticholinergic agents. What would be the instructor's best response?
Correct answer
D
Rationale
The correct answer is D: They act to block the effects of the parasympathetic nervous system. Anticholinergic agents inhibit the action of acetylcholine, the primary neurotransmitter of the parasympathetic nervous system. By blocking muscarinic acetylcholine receptors, these agents reduce parasympathetic stimulation, leading to effects such as decreased salivation, decreased GI motility, and pupil dilation.
Choice A is incorrect because anticholinergic agents do not compete with serotonin for receptor sites; they primarily target acetylcholine receptors. Choice B is incorrect as anticholinergic agents do not directly affect norepinephrine levels at the neuromuscular junction. Choice C is incorrect because anticholinergic agents primarily target muscarinic receptors, not nicotinic receptors.
Choice A is incorrect because anticholinergic agents do not compete with serotonin for receptor sites; they primarily target acetylcholine receptors. Choice B is incorrect as anticholinergic agents do not directly affect norepinephrine levels at the neuromuscular junction. Choice C is incorrect because anticholinergic agents primarily target muscarinic receptors, not nicotinic receptors.