A 67-year-old man presents to the emergency department because of acute chest pain that began more than 6 hours ago. ECG shows elevated ST-segments in three consecutive leads. If a biopsy of the affected tissue were taken at this point, bands would be visible under the microscope. What is the best explanation for the presence of these bands?

A. Collagen deposits of fibrosis
B. Elevated intracellular calcium level
C. Inability to form cross-bridges between myosin and actin
D. Macrophage-mediated resorption

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A 25-year-old man comes to the physician with constipation, polyuria, polydipsia, hyporeflexia, and lethargy. Laboratory studies confirm an abnormality in calcium handling. Which of the following drugs would most likely alleviate these symptoms?

A. Acetazolamide
B. Furosemide
C. Hydrochlorothiazide
D. Mannitol
E. Parathyroid hormone

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A 42-year-old man presented to his primary care physician several months ago with complaints of fatigue, loss of appetite, difficulty concentrating, decreased sleep, and feelings of worthlessness. He has been receiving pharmacologic treatment for these symptoms and has now begun to develop symptoms of urinary retention, blurred vision, constipation, and aggravation of his glaucoma. Which of the following drugs is this patient most likely taking?

A. Bupropion
B. Fluoxetine
C. Nortriptyline
D. Phenelzine
E. Trazodone

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An infant is born prematurely at 34 weeks’ gestation. At birth he exhibits a grimace and has a pink trunk with blue extremities, a pulse of 85/min, some muscle tone, and a respiratory rate of 25/min. What is the infant’s Apgar score?

A. 5
B. 6
C. 7
D. 8
E. 9

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The diagram shows a cross-section of normal human skin. Pemphigus vulgaris patients suffer from production of autoantibodies against which of the following labeled layers in this image?

A. A
B. B
C. C
D. D
E. E

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After a brain tumor resection, a right-handed patient comes to the office with this wife. The wife reports that her husband can no longer balance his checkbook or count his money. Recently he has also had difficulty identifying individual fingers and confuses his left and right sides. Additionally, she reports that although he can read without effort, he has extreme difficulty writing. The damage can be localized to which of the following areas of the brain?

A. Left angular gyrus
B. Left posterior inferior frontal lobe
C. Left posterior superior temporal gyrus
D. Left sylvian region
E. Left temporoparieto-occipital junction

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A 3-year-old boy is brought to the pediatrician because of decreased vision and pain in his right eye. Past medical history is significant for the diagnosis of glaucoma shortly after birth that has been refractory to standard medical therapies. Focused physical examination reveals iris hamartomas. Which of the following additional signs is most likely on physical examination?

A. Bilateral acoustic neuromas
B. Bilateral renal cell carcinomas
C. Cystic medial necrosis of the aorta
D. Leptomeningeal angioma
E. Scoliosis

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A 38-year-old woman comes to the physician with a 4-month history of episodic nausea and a sensation of abnormal motion that lasts for 4-5 minutes. Her symptoms have intensified over the past week, and the episodes now last more than an hour. A particularly severe episode this morning resulted in vomiting and buzzing in her right ear. On physical examination, the patient appears healthy with normal vital signs, mild sensorineural hearing loss in the right ear, and no nystagmus. The patient’s laboratory tests are unremarkable. Audiologic testing demonstrates unilateral hearing loss on the right side, most pronounced in the low-frequency range. Which of the following locations is the most likely origin of the abnormality responsible for this patient’s symptoms?

A. Cochlea
B. Endolymphatic sac
C. Semicircular canals
D. Utricle and saccule
E. Vestibulocochlear nerve

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Myasthenia gravis is an autoimmune disorder that affects approximately 3 in 100,000 people. Individuals with mysasthenia gravis classically present with complaints of muscle weakness and fatigue secondary to the formation of autoantibodies directed against the acetylcholine receptors at neuromuscular junctions. The most accurate method of diagnosis involves the detection of these autoantibodies. On average, this test is approximately 80% sensitive and 90% specific. If an individual has a positive test for autoantibodies against the acetylcholine receptor, what is the approximate post-test probability of having this disease, assuming a pre-test probability of 50%?

A. 80%
B. 85%
C. 89%
D. 90%
E. 95%
F. 99%

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Sympathetic effects on the heart are activated via the neurotransmitter norepinephrine acting on ?1-receptors. The effects are manifest in positive chronotropy, dromotropy, and inotropy. Which of the following sympathetic effects is correctly paired with its physiologic mechanism?

A. Chronotropic effect: decreased inward Na+ current
B. Chronotropic effect: increased inward Ca2+ current
C. Dromotropic effect: increased inward Ca2+ current
D. Dromotropic effect: increased inward Na+ current
E. Inotropic effect: decreased inward Ca2+ current

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