Pathophysiology Practice Exam

Correct Answer: A

Rationale: The correct answer is Electromyography (EMG). EMG is commonly used to diagnose conditions involving muscle weakness and fatigue, such as myasthenia gravis. Nerve conduction studies primarily assess nerve function rather than muscle involvement. While a muscle biopsy can provide valuable information, EMG is more specific for evaluating muscle function in this context. A blood test for autoantibodies may be helpful in certain autoimmune conditions but is not the primary test for confirming the diagnosis based on the patient's symptoms of muscle weakness and fatigue.

Correct Answer: C

Rationale: The correct answer is C. Raloxifene is a selective estrogen receptor modulator (SERM) used to prevent bone loss. It should be taken with food to reduce gastrointestinal side effects, not on an empty stomach. Choices A and B are incorrect because raloxifene is indeed a SERM that prevents bone loss, but it does not directly work by increasing bone formation or decreasing bone resorption. Choice D is incorrect as weight gain and fluid retention are not common side effects of raloxifene.

Correct Answer: C

Rationale: When the maternal immune system becomes sensitized against antigens expressed by the fetus, an alloimmune reaction occurs. In this situation, the mother's immune system recognizes the fetus as foreign due to differences in antigens, leading to an immune response against the fetus. Choice A, 'Autoimmune,' is incorrect because it refers to the immune system mistakenly attacking the body's own cells and tissues. Choice B, 'Anaphylaxis,' is not the correct answer as it is a severe allergic reaction that can be life-threatening. Choice D, 'Allergic,' is also incorrect as it refers to an immune response triggered by allergens, not antigens expressed by the fetus.

Correct Answer: C

Rationale: Rifampin (Rifadin) achieves a therapeutic action against both intracellular and extracellular tuberculosis organisms by inhibiting the synthesis of RNA. This action interferes with bacterial RNA synthesis, leading to the suppression of protein synthesis in the bacteria, ultimately causing their death. Option A is incorrect because rifampin is primarily metabolized in the liver, but this is not how it exerts its bactericidal effects. Option B is incorrect as rifampin does not bind to acetylcholine. Option D is also incorrect as rifampin does not cause phagocytosis.

Correct Answer: B

Rationale: The correct answer is B: Size. Muscular atrophy is characterized by a reduction in the size of muscle cells. This decrease in size can be due to various factors such as disuse, aging, or disease. Choice A, Number, is incorrect because muscular atrophy does not involve a decrease in the number of muscle cells but rather their size. Choice C, Vacuoles, is incorrect as vacuoles are not directly related to the definition of muscular atrophy. Choice D, Lipofuscin, is incorrect as lipofuscin is a pigment associated with aging and has no direct connection to the decrease in muscle cell size seen in muscular atrophy.