Correct Answer: A

Rationale: HRT is associated with an increased risk of cardiovascular events, including heart attack and stroke, particularly in patients with a history of cardiovascular disease.

Correct Answer: B

Rationale: The correct answer is B: 'Use of nitrates.' Tadalafil (Cialis) is contraindicated in patients taking nitrates due to the risk of severe hypotension. Nitrates and Cialis both cause vasodilation, which can lead to a dangerous drop in blood pressure when used together. Choices A, C, and D are incorrect because a history of hypertension, use of antihypertensive medications, and a history of peptic ulcer disease are not specific contraindications for tadalafil use.

Correct Answer: B

Rationale: Hepatic encephalopathy is caused by increased ammonia levels in the bloodstream. Ammonia, a byproduct of protein metabolism normally processed by the liver, accumulates in the bloodstream when the liver is unable to function properly. This excess ammonia affects brain function, leading to symptoms of hepatic encephalopathy. Choices A, C, and D are incorrect because they do not directly relate to the pathophysiology of hepatic encephalopathy.

Correct Answer: C

Rationale: The correct answer is C: 'Improved secondary sexual characteristics.' Testosterone therapy in patients with hypogonadism typically leads to improved secondary sexual characteristics, which include increased muscle mass and libido. While increased libido (choice A) and increased muscle mass (choice B) are effects of testosterone therapy, they are more specific outcomes related to secondary sexual characteristics. Decreased sperm count (choice D) would not be an expected outcome of testosterone therapy for hypogonadism, as testosterone is essential for sperm production.

Correct Answer: D

Rationale: The autonomic nervous system controls involuntary bodily functions like heart rate, respiration, and sweating. In the given scenario, the 'fight or flight' response is activated, leading to increased heart rate, palpitations, anxiety, and shaky hands. The cerebral cortex is involved in conscious thought processes and decision-making, not the immediate physiological response observed here. The somatic nervous system regulates voluntary movements, while the limbic system is responsible for emotions and memory, but the autonomic nervous system is primarily responsible for the physiological responses seen in this situation.