100% COMSAE Phase 1 Form 113
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2025|2026 Q&A | Instant
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1. Which of the following structures is located in the posterior
mediastinum?
A. Thymus
B. Heart
C. Descending aorta
D. Phrenic nerve
Correct ,,,,answer,,,,: C
Rationale: The posterior mediastinum contains the descending thoracic
aorta, esophagus, thoracic duct, azygos system, and sympathetic
chains. The thymus is in the anterior mediastinum, the heart in the
middle.
2. A 55-year-old man has difficulty with fine motor control and intention
tremor when reaching for objects. He also has dysdiadochokinesia.
Which part of the brain is most likely affected?
A. Frontal lobe
B. Cerebellum
C. Basal ganglia
D. Thalamus
,Correct ,,,,answer,,,,: B
Rationale: The cerebellum coordinates voluntary movements; lesions
cause ataxia, dysmetria, intention tremor, and dysdiadochokinesia.
3. Which of the following enzymes catalyzes the committed step in
cholesterol biosynthesis and is the target of statins?
A. HMG-CoA synthase
B. HMG-CoA reductase
C. Acetyl-CoA carboxylase
D. Thiolase
Correct ,,,,answer,,,,: B
Rationale: HMG-CoA reductase converts HMG-CoA to mevalonate and
is the rate-limiting enzyme in cholesterol synthesis. Statins competitively
inhibit it.
4. A Gram-negative, oxidase-positive, motile rod isolated from a burn
wound with a green-blue pigment is most likely:
A. Escherichia coli
B. Pseudomonas aeruginosa
C. Klebsiella pneumoniae
D. Proteus mirabilis
Correct ,,,,answer,,,,: B
Rationale: P. aeruginosa is an opportunistic pathogen known for
pyocyanin (blue-green pigment), oxidase positivity, and causing
infections in burn patients and immunocompromised hosts.
5. During an osteopathic structural exam, a patient has a rotated and
sidebent lumbar segment. The physician notes the segment is restricted
in motion. This is best described as:
A. Somatic dysfunction
B. Sprain
,C. Strain
D. Myofascial trigger point
Correct ,,,,answer,,,,: A
Rationale: Somatic dysfunction is defined as impaired or altered
function of related components of the somatic system: skeletal,
arthrodial, and myofascial structures, and their related vascular,
lymphatic, and neural elements.
6. The sodium-potassium ATPase pump transports:
A. 3 Na+ out, 2 K+ in
B. 2 Na+ out, 3 K+ in
C. 3 Na+ in, 2 K+ out
D. 2 Na+ in, 3 K+ out
Correct ,,,,answer,,,,: A
Rationale: The Na+/K+-ATPase actively transports 3 sodium ions out of
the cell and 2 potassium ions into the cell, maintaining the
electrochemical gradient.
7. A 45-year-old woman with Hashimoto thyroiditis has low T4 and
elevated TSH. Her thyroid gland shows diffuse lymphocytic infiltration on
biopsy. This is an example of which type of hypersensitivity?
A. Type I
B. Type II
C. Type III
D. Type IV
Correct ,,,,answer,,,,: D (and also II? Hashimoto's is predominantly a
type IV hypersensitivity with T-cell mediated destruction, though anti-
thyroid antibodies (type II) are present. The main mechanism of tissue
damage is type IV. I'll ,,,,answer,,,, D.)
Rationale: Hashimoto thyroiditis is primarily a type IV (cell-mediated)
, hypersensitivity with CD8+ T-cell destruction of thyroid follicles, though
antibodies also contribute.
8. Which vitamin deficiency causes Wernicke-Korsakoff syndrome,
characterized by ataxia, confusion, and ophthalmoplegia?
A. Thiamine (B1)
B. Riboflavin (B2)
C. Niacin (B3)
D. Pyridoxine (B6)
Correct ,,,,answer,,,,: A
Rationale: Thiamine deficiency leads to Wernicke encephalopathy (triad:
ataxia, ophthalmoplegia, confusion) and Korsakoff psychosis
(confabulation, memory loss), often in alcoholics.
9. A 4-year-old child with a history of recurrent pneumonias, failure to
thrive, and bulky, foul-smelling stools is diagnosed with cystic fibrosis.
The primary defect is in a protein that functions as a:
A. Sodium channel
B. Chloride channel (CFTR)
C. Potassium channel
D. Calcium channel
Correct ,,,,answer,,,,: B
Rationale: CFTR is a cAMP-regulated chloride channel; mutations cause
defective chloride transport, leading to thick secretions in lungs,
pancreas, and other organs.
10. A patient with right-sided heart failure would most likely exhibit:
A. Pulmonary edema
B. Orthopnea
C. Hepatomegaly and peripheral edema
D. Pink frothy sputum
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2025|2026 Q&A | Instant
Download Pdf
1. Which of the following structures is located in the posterior
mediastinum?
A. Thymus
B. Heart
C. Descending aorta
D. Phrenic nerve
Correct ,,,,answer,,,,: C
Rationale: The posterior mediastinum contains the descending thoracic
aorta, esophagus, thoracic duct, azygos system, and sympathetic
chains. The thymus is in the anterior mediastinum, the heart in the
middle.
2. A 55-year-old man has difficulty with fine motor control and intention
tremor when reaching for objects. He also has dysdiadochokinesia.
Which part of the brain is most likely affected?
A. Frontal lobe
B. Cerebellum
C. Basal ganglia
D. Thalamus
,Correct ,,,,answer,,,,: B
Rationale: The cerebellum coordinates voluntary movements; lesions
cause ataxia, dysmetria, intention tremor, and dysdiadochokinesia.
3. Which of the following enzymes catalyzes the committed step in
cholesterol biosynthesis and is the target of statins?
A. HMG-CoA synthase
B. HMG-CoA reductase
C. Acetyl-CoA carboxylase
D. Thiolase
Correct ,,,,answer,,,,: B
Rationale: HMG-CoA reductase converts HMG-CoA to mevalonate and
is the rate-limiting enzyme in cholesterol synthesis. Statins competitively
inhibit it.
4. A Gram-negative, oxidase-positive, motile rod isolated from a burn
wound with a green-blue pigment is most likely:
A. Escherichia coli
B. Pseudomonas aeruginosa
C. Klebsiella pneumoniae
D. Proteus mirabilis
Correct ,,,,answer,,,,: B
Rationale: P. aeruginosa is an opportunistic pathogen known for
pyocyanin (blue-green pigment), oxidase positivity, and causing
infections in burn patients and immunocompromised hosts.
5. During an osteopathic structural exam, a patient has a rotated and
sidebent lumbar segment. The physician notes the segment is restricted
in motion. This is best described as:
A. Somatic dysfunction
B. Sprain
,C. Strain
D. Myofascial trigger point
Correct ,,,,answer,,,,: A
Rationale: Somatic dysfunction is defined as impaired or altered
function of related components of the somatic system: skeletal,
arthrodial, and myofascial structures, and their related vascular,
lymphatic, and neural elements.
6. The sodium-potassium ATPase pump transports:
A. 3 Na+ out, 2 K+ in
B. 2 Na+ out, 3 K+ in
C. 3 Na+ in, 2 K+ out
D. 2 Na+ in, 3 K+ out
Correct ,,,,answer,,,,: A
Rationale: The Na+/K+-ATPase actively transports 3 sodium ions out of
the cell and 2 potassium ions into the cell, maintaining the
electrochemical gradient.
7. A 45-year-old woman with Hashimoto thyroiditis has low T4 and
elevated TSH. Her thyroid gland shows diffuse lymphocytic infiltration on
biopsy. This is an example of which type of hypersensitivity?
A. Type I
B. Type II
C. Type III
D. Type IV
Correct ,,,,answer,,,,: D (and also II? Hashimoto's is predominantly a
type IV hypersensitivity with T-cell mediated destruction, though anti-
thyroid antibodies (type II) are present. The main mechanism of tissue
damage is type IV. I'll ,,,,answer,,,, D.)
Rationale: Hashimoto thyroiditis is primarily a type IV (cell-mediated)
, hypersensitivity with CD8+ T-cell destruction of thyroid follicles, though
antibodies also contribute.
8. Which vitamin deficiency causes Wernicke-Korsakoff syndrome,
characterized by ataxia, confusion, and ophthalmoplegia?
A. Thiamine (B1)
B. Riboflavin (B2)
C. Niacin (B3)
D. Pyridoxine (B6)
Correct ,,,,answer,,,,: A
Rationale: Thiamine deficiency leads to Wernicke encephalopathy (triad:
ataxia, ophthalmoplegia, confusion) and Korsakoff psychosis
(confabulation, memory loss), often in alcoholics.
9. A 4-year-old child with a history of recurrent pneumonias, failure to
thrive, and bulky, foul-smelling stools is diagnosed with cystic fibrosis.
The primary defect is in a protein that functions as a:
A. Sodium channel
B. Chloride channel (CFTR)
C. Potassium channel
D. Calcium channel
Correct ,,,,answer,,,,: B
Rationale: CFTR is a cAMP-regulated chloride channel; mutations cause
defective chloride transport, leading to thick secretions in lungs,
pancreas, and other organs.
10. A patient with right-sided heart failure would most likely exhibit:
A. Pulmonary edema
B. Orthopnea
C. Hepatomegaly and peripheral edema
D. Pink frothy sputum
