A patient is receiving heparin therapy as part of the treatment for a pulmonary embolism. The nurse monitors the results of which laboratory test to check the drug’s effectiveness?

Correct Answer: B

Rationale: The correct answer is B: Activated partial thromboplastin time (aPTT). This test is specifically used to monitor heparin therapy's effectiveness by measuring the blood's clotting time. Heparin works by inhibiting blood clot formation, so monitoring aPTT helps ensure the patient is within the therapeutic range to prevent clot formation. Incorrect choices: A: Bleeding times - This test assesses how long it takes for blood to clot, but it does not specifically monitor heparin therapy's effectiveness. C: Prothrombin time/international normalized ratio (PT/INR) - This test is used to monitor warfarin therapy, not heparin therapy. D: Vitamin K levels - Monitoring vitamin K levels is not relevant to assessing heparin therapy's effectiveness in preventing clot formation.

Correct Answer: B

Rationale: The correct answer is B because metabolic transformation (phase 1) involves the conversion of substances through oxidation, reduction, or hydrolysis processes, which alter the chemical structure of the compound. This phase prepares the substance for further metabolism or excretion. Acetylation and methylation (choice A) involve different enzymatic processes unrelated to phase 1 metabolism. Glucuronide formation (choice C) is part of phase 2 metabolism, not phase 1. Binding to plasma proteins (choice D) is not a metabolic transformation process but rather a mechanism of distribution in the body.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Idiosyncratic reaction refers to unusual, unpredictable responses to a drug. 2. Choice C correctly defines idiosyncratic reaction as inherent, abnormal, and unpredictable. 3. Choices A and B are incorrect as they do not accurately describe idiosyncratic reactions. 4. Choice A refers to hypersensitivity reactions, not idiosyncratic reactions. 5. Choice B refers to drug antagonism, which is different from idiosyncratic reactions. 6. Choice D is incorrect as it describes a quantitatively exaggerated response, not an idiosyncratic reaction. Summary: Choice C is correct as it accurately defines idiosyncratic reactions. Choices A, B, and D are incorrect as they describe different concepts that do not align with the definition of idiosyncratic reactions.

Correct Answer: C

Rationale: Muscarinic receptors are located in autonomic effector cells. These receptors respond to acetylcholine released by parasympathetic nerves in organs like the heart, smooth muscle, and glands. They play a key role in regulating functions such as heart rate, digestion, and glandular secretions. Autonomic ganglia (A) contain nicotinic receptors, not muscarinic. Skeletal muscle neuromuscular junctions (B) have nicotinic receptors. Sensory carotid sinus baroreceptor zone (D) is not directly involved in cholinergic signaling. Hence, the correct answer is C.

Correct Answer: A

Rationale: Atropine causes spasmolitic activity by blocking acetylcholine receptors, leading to relaxation of smooth muscles. This is beneficial in conditions like irritable bowel syndrome. Intestinal hypermotility, stimulation of gut contraction, and secretory activity are all effects opposite to what atropine causes due to its anticholinergic properties. Atropine's mechanism of action supports choice A as the correct answer.