Correct Answer: A

Rationale: The correct answer is A: 'Relaxation of the muscles in the prostate and bladder neck, leading to improved urinary flow.' Tamsulosin is an alpha-blocker that specifically targets alpha-1 receptors in the prostate and bladder neck, causing relaxation of smooth muscles. This relaxation results in improved urinary flow and reduced symptoms of BPH. Choice B is incorrect because while tamsulosin does improve urinary flow, it does not directly increase urine flow. Choice C is incorrect because tamsulosin does not reduce prostate size. Choice D is incorrect as tamsulosin does not have a primary effect on erectile function.

Correct Answer: C

Rationale: Filgrastim (Neupogen) is a medication that promotes the growth of white blood cells. In the context of ischemic heart disease, promoting angiogenesis, the formation of new blood vessels, can improve blood flow to the heart muscle, reducing ischemia and potentially improving cardiac function. Therefore, the correct answer is C. Choices A and B are incorrect because filgrastim does not directly affect platelet levels. Choice D is also incorrect as filgrastim does not prevent thrombus formation.

Correct Answer: B

Rationale: The correct answer is B. Raloxifene, a selective estrogen receptor modulator (SERM), primarily works by decreasing bone resorption and increasing bone density. This mechanism of action helps in the prevention and treatment of osteoporosis by maintaining or improving bone strength. Choice A is incorrect because raloxifene does not directly stimulate the formation of new bone but rather helps in preserving existing bone. Choice C is incorrect because raloxifene does not increase the excretion of calcium through the kidneys; instead, it acts on bone tissue. Choice D is incorrect as raloxifene does not directly increase calcium absorption in the intestines but rather focuses on bone health.

Correct Answer: B

Rationale: The correct answer is B. Axonal transport involves the movement of materials to the nerve terminal by either fast or slow components, which is essential for cell survival. Choice A is incorrect because while anterograde and retrograde axonal transport are involved in the movement of materials, they do not specifically relate to the communication of nerve impulses between a neuron and the CNS. Choice C is incorrect because the unidirectional nature of axonal transport does not primarily function to protect the CNS against pathogens. Choice D is incorrect as axonal transport is responsible for the movement of various materials, not just electrical impulses.

Correct Answer: A

Rationale: When starting on oral contraceptives, it is crucial to take them at the same time each day to maintain stable hormone levels and ensure their effectiveness in preventing pregnancy. Choice B is incorrect because consistency in timing is essential to maximize contraceptive efficacy. Choice C is incorrect as there is no evidence that taking oral contraceptives in the morning helps avoid nighttime side effects. Choice D is incorrect because oral contraceptives do not provide immediate effectiveness and require consistent use to prevent pregnancy.