(Standard Text and Image Format) (2026
Edition): Comprehensive Multiple-Choice
Questions, Answers, and Detailed
Rationales
Question 1
A 65-year-old man develops chest pain while mowing his
lawn. The pain resolves with rest. Which mechanism most
likely explains his symptoms?
A. Coronary vasospasm at rest
B. Fixed atherosclerotic narrowing causing demand ischemia
C. Complete coronary artery occlusion
D. Acute pericarditis
E. Pulmonary embolism
Answer: B. Fixed atherosclerotic narrowing causing demand
ischemia
Stable angina occurs when myocardial oxygen demand
exceeds supply because of fixed coronary artery stenosis.
Symptoms are reproducibly triggered by exertion and relieved
by rest or nitroglycerin.
Question 2
,A researcher administers a drug that competitively inhibits an
enzyme. Which effect is expected?
A. Decreased Km and decreased Vmax
B. Increased Km and decreased Vmax
C. Increased Km with unchanged Vmax
D. Unchanged Km and decreased Vmax
E. Increased Km and increased Vmax
Answer: C. Increased Km with unchanged Vmax
Competitive inhibitors compete with substrate for the active
site. More substrate can overcome inhibition, so Vmax
remains unchanged while apparent Km increases.
Question 3
A 5-year-old child presents with recurrent respiratory
infections and absent thymic shadow on chest radiograph.
Which embryologic structure failed to develop properly?
A. First pharyngeal pouch
B. Second pharyngeal pouch
C. Third and fourth pharyngeal pouches
D. Neural crest of the forebrain
E. Somites
Answer: C. Third and fourth pharyngeal pouches
DiGeorge syndrome results from abnormal development of
the third and fourth pharyngeal pouches, causing thymic and
parathyroid hypoplasia.
,Question 4
A patient with chronic alcohol use develops confusion,
ophthalmoplegia, and ataxia. Which vitamin deficiency is
responsible?
A. Vitamin B12
B. Vitamin C
C. Vitamin B6
D. Thiamine
E. Folate
Answer: D. Thiamine
Wernicke encephalopathy is caused by thiamine deficiency.
The classic triad includes confusion, ophthalmoplegia, and
ataxia.
Question 5
A woman develops hyperthyroidism with diffuse goiter and
exophthalmos. Which antibody is most likely present?
A. Anti-thyroglobulin antibody
B. Anti-dsDNA antibody
C. TSH receptor–stimulating antibody
D. Anti-centromere antibody
E. Anti-mitochondrial antibody
Answer: C. TSH receptor–stimulating antibody
Graves disease is caused by IgG antibodies that stimulate TSH
receptors, resulting in excessive thyroid hormone production.
, Question 6
Which cranial nerve provides motor innervation to the lateral
rectus muscle?
A. Oculomotor nerve
B. Trochlear nerve
C. Trigeminal nerve
D. Abducens nerve
E. Facial nerve
Answer: D. Abducens nerve
The abducens nerve (CN VI) innervates the lateral rectus
muscle, which abducts the eye.
Question 7
A patient with nephrotic syndrome is most likely to
experience which complication?
A. Hypercoagulability
B. Metabolic acidosis
C. Hypercalcemia
D. Polycythemia
E. Hypermagnesemia
Answer: A. Hypercoagulability
Loss of antithrombin III and other anticoagulant proteins in
the urine increases the risk of thrombosis in nephrotic
syndrome.