Correct Answer: A

Rationale: The correct answer is A because sildenafil should not be taken with medications containing nitrates, such as nitroglycerin, due to the risk of severe hypotension. Choice B is incorrect because priapism (prolonged erection) is a serious side effect but does not require immediate intervention like severe hypotension. Choice C is incorrect as it correctly identifies a contraindication for sildenafil use. Choice D is incorrect because not all over-the-counter medications are safe to take with sildenafil, and interactions can occur.

Correct Answer: B

Rationale: The correct answer is B: 'Use of nitrates.' Sildenafil (Viagra) is contraindicated in patients taking nitrates due to the risk of severe hypotension. Nitrates and sildenafil both cause vasodilation, and their combined use can lead to a dangerous drop in blood pressure. Choices A, C, and D are incorrect because a history of hypertension, recent use of antihypertensive medications, or a history of peptic ulcer disease are not direct contraindications for using sildenafil.

Correct Answer: D

Rationale: Neutrophils are the correct answer as they are the predominant phagocytes arriving early at inflammatory and infection sites. Neutrophils are part of the body's innate immune system and are among the first responders to sites of inflammation or infection. They play a crucial role in engulfing and destroying pathogens. Macrophages, although important phagocytes, usually arrive later at the site. Mast cells are involved in allergic reactions and not primarily phagocytes. Monocytes are precursors to macrophages and are not the predominant phagocytes arriving early at inflammatory sites.

Correct Answer: B

Rationale: The correct answer is B: Increased gastric motility. The parasympathetic nervous system is known to promote rest and digest functions, which includes increasing gastric motility to aid in digestion. Choices A, C, and D are incorrect as they are more characteristic of the sympathetic nervous system. The sympathetic nervous system is responsible for the fight or flight response, leading to increased heart rate (Choice A), pupil dilation (Choice C), and sweating (Choice D) among other responses.

Correct Answer: B

Rationale: The correct answer is B. Damage to the vagus nerve can result in the loss of the gag reflex, which is a key indicator for the neurologist. Difficulty swallowing (Choice A) is more associated with issues related to the glossopharyngeal nerve (CN IX) and hypoglossal nerve (CN XII). An inability to smell (Choice C) is related to the olfactory nerve (CN I), and impaired eye movement (Choice D) is typically associated with damage to the oculomotor nerve (CN III), trochlear nerve (CN IV), or abducens nerve (CN VI), not the vagus nerve.