Pathophysiology Practice Exam

Correct Answer: B

Rationale: Acetylcholine acts as an inhibitory neurotransmitter at the sinoatrial node. It slows down the heart rate by decreasing the firing rate of the sinoatrial node, which serves as the heart's natural pacemaker. Neurotransmitters do not have a charge, so choice A is incorrect. Choice C is wrong as overstimulation is not a characteristic of acetylcholine at the sinoatrial node. Choice D is also incorrect because acetylcholine actively influences heart rate regulation when released at the sinoatrial node.

Correct Answer: A

Rationale: An attenuated antigen used in a vaccine is alive but less infectious, aiming to stimulate an immune response. Choice B is incorrect because an attenuated antigen is not highly infectious. Choice C is incorrect as the antigen is intentionally altered to be less infectious. Choice D is incorrect as an attenuated antigen is not infectious.

Correct Answer: C

Rationale: In patients receiving testosterone therapy, the nurse should prioritize assessing serum calcium levels. Testosterone therapy can lead to hypercalcemia, making the evaluation of serum calcium levels crucial. Skin inspection for developing lesions, lung function testing, and arterial blood gas assessment are not the priority assessments for potential adverse effects of testosterone therapy. Skin inspection may be relevant for dermatological side effects, lung function testing and arterial blood gas assessment are not directly related to the common side effects of testosterone therapy.

Correct Answer: C

Rationale: Ivermectin (Stromectol) is commonly used to treat parasitic infections, particularly Strongyloides stercoralis. This parasitic infection is known to respond well to Ivermectin therapy. Entamoeba histolytica causes amoebiasis and is typically treated with antiprotozoal drugs like metronidazole, not Ivermectin. Giardia lamblia is a protozoan parasite causing giardiasis, which is usually treated with medications like metronidazole or tinidazole, not Ivermectin. Plasmodium falciparum is a malaria-causing parasite and is not treated with Ivermectin but with antimalarial medications like chloroquine or artemisinin-based combination therapies.

Correct Answer: B

Rationale: Acetylcholine acts as an inhibitory neurotransmitter at the sinoatrial node. It slows down the heart rate by decreasing the firing rate of the sinoatrial node, which serves as the heart's natural pacemaker. Neurotransmitters do not have a charge, so choice A is incorrect. Choice C is wrong as overstimulation is not a characteristic of acetylcholine at the sinoatrial node. Choice D is also incorrect because acetylcholine actively influences heart rate regulation when released at the sinoatrial node.