QUESTIONS AND ANSWERS | PLUS
RATIONALES | STUDY GUIDE
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,Question 1: During a COMSAE Phase 1 examination, a student recalls that a
patient with a lesion in the right cerebral hemisphere experiences left-sided
hemiparesis. Which tract is primarily responsible for this motor deficit?
A. Dorsal column-medial lemniscus pathway
B. Lateral corticospinal tract
C. Spinothalamic tract
D. Rubrospinal tract
CORRECT ANSWER: B. Lateral corticospinal tract
Rationale: The lateral corticospinal tract decussates in the medulla and controls
voluntary skilled movements of the contralateral limbs. A right hemisphere lesion
affects the left side of the body via this tract, consistent with upper motor neuron
signs in clinical vignettes commonly tested in COMSAE Phase 1.
Question 2: A 45-year-old male presents with fatigue, weight gain, and cold
intolerance. Laboratory results show elevated TSH and low free T4. Which cell
type in the thyroid is primarily affected in this autoimmune condition?
A. Parafollicular C cells
B. Follicular cells
C. Chief cells
D. Oxyphil cells
CORRECT ANSWER: B. Follicular cells
Rationale: Hashimoto thyroiditis, the most common cause of primary
hypothyroidism, involves autoimmune destruction of thyroid follicular cells leading
to decreased thyroid hormone production, elevated TSH, and the classic symptoms
described.
Question 3: In a biochemical pathway, glucose-6-phosphate is converted to 6-
phosphogluconolactone in the first step of a specific metabolic process. This
process generates NADPH and is crucial for which cellular function?
A. Glycolysis energy production
B. Fatty acid synthesis and antioxidant defense
C. Krebs cycle ATP generation
D. Glycogenolysis
CORRECT ANSWER: B. Fatty acid synthesis and antioxidant defense
Rationale: The pentose phosphate pathway (hexose monophosphate shunt)
produces NADPH, which is essential for reductive biosynthesis such as fatty acid and
cholesterol synthesis and for maintaining glutathione in its reduced form to combat
oxidative stress.
Question 4: A patient with a history of recurrent sinopulmonary infections and
diarrhea is found to have absent B cells and low immunoglobulins. Which
primary immunodeficiency is most likely?
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,A. DiGeorge syndrome
B. X-linked agammaglobulinemia
C. Chronic granulomatous disease
D. SCID
CORRECT ANSWER: B. X-linked agammaglobulinemia
Rationale: Bruton agammaglobulinemia (X-linked) results from defective B-cell
maturation due to BTK gene mutation, leading to absent B cells, low Igs, and
recurrent bacterial infections after maternal antibodies wane.
Question 5: Which neurotransmitter is primarily used by the preganglionic
neurons in both the sympathetic and parasympathetic divisions of the
autonomic nervous system?
A. Norepinephrine
B. Acetylcholine
C. Dopamine
D. Serotonin
CORRECT ANSWER: B. Acetylcholine
Rationale: All preganglionic autonomic fibers release acetylcholine onto nicotinic
receptors. Postganglionic sympathetic fibers release norepinephrine (except sweat
glands), while parasympathetic postganglionic fibers release acetylcholine.
Question 6: A 55-year-old patient with long-standing hypertension develops
microalbuminuria. Which vascular change is most characteristic of the
underlying renal pathology?
A. Hyperplastic arteriolosclerosis
B. Hyaline arteriolosclerosis
C. Fibrinoid necrosis
D. Medial calcification
CORRECT ANSWER: B. Hyaline arteriolosclerosis
Rationale: Benign nephrosclerosis from chronic hypertension features hyaline
thickening of arteriolar walls, leading to ischemic changes and microalbuminuria as
an early sign of kidney damage.
Question 7: In pharmacology, a drug that competitively inhibits HMG-CoA
reductase is used to lower cholesterol. What is the primary mechanism by
which this drug class reduces LDL levels?
A. Increased bile acid excretion
B. Upregulation of hepatic LDL receptors
C. Decreased intestinal cholesterol absorption
D. Increased VLDL secretion
CORRECT ANSWER: B. Upregulation of hepatic LDL receptors
Rationale: Statins inhibit HMG-CoA reductase, reducing intracellular cholesterol in
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, hepatocytes. This leads to increased expression of LDL receptors, enhancing
clearance of LDL from the blood.
Question 8: A histologic section of lung tissue from a smoker shows squamous
metaplasia of the bronchial epithelium. This change is best described as?
A. Dysplasia
B. Reversible replacement of one differentiated cell type by another
C. Irreversible neoplastic transformation
D. Hyperplasia
CORRECT ANSWER: B. Reversible replacement of one differentiated cell type
by another
Rationale: Metaplasia is an adaptive, reversible change where one adult cell type
replaces another, commonly seen in smokers' bronchial epithelium as a protective
response to chronic irritation.
Question 9: Which vitamin deficiency leads to impaired wound healing, scurvy,
and defective collagen synthesis due to problems with hydroxylation?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
CORRECT ANSWER: B. Vitamin C
Rationale: Ascorbic acid (Vitamin C) is a cofactor for prolyl and lysyl hydroxylases
necessary for collagen cross-linking and stability. Deficiency causes scurvy with poor
wound healing and bleeding tendencies.
Question 10: In a patient with acute pancreatitis, which laboratory finding is
most specific for the diagnosis?
A. Elevated serum amylase
B. Elevated serum lipase
C. Hypocalcemia
D. Hyperglycemia
CORRECT ANSWER: B. Elevated serum lipase
Rationale: Lipase is more specific than amylase for acute pancreatitis as it remains
elevated longer and is less affected by non-pancreatic conditions.
Question 11: The osteopathic concept of somatic dysfunction involves
impaired function of related components. Which of the following is a key
TART criterion used in diagnosis?
A. Texture, Asymmetry, Restriction, Tenderness
B. Temperature, Alignment, Range, Tone
C. Trauma, Age, Referral, Treatment
D. Tissue, Activity, Reflex, Tension
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