COMSAE Form 113 Practice Exam Version
1 Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
Section 1: Foundational Biomedical Sciences (Questions 1-20)
Q1. The primary motor cortex responsible for voluntary movement is located
in which of the following gyri?
• A) Superior temporal gyrus
• B) Precentral gyrus
• C) Postcentral gyrus
• D) Inferior frontal gyrus
Correct Answer: B
Rationale: The precentral gyrus is the location of the primary motor cortex
(Brodmann area 4), which is responsible for planning and executing voluntary
movements.
Q2. Which amino acid serves as the precursor for nitric oxide (NO) synthesis
in endothelial cells?
• A) L-Arginine
• B) L-Citrulline
• C) L-Glutamate
• D) L-Lysine
, Correct Answer: A
Rationale: The amino acid L-arginine is the substrate for nitric oxide synthase
(eNOS), which produces the vasodilator nitric oxide in the vascular endothelium.
Q3. A patient presents with a tumor that is found to be secreting excessive
parathyroid hormone (PTH). Which of the following laboratory findings
would be expected?
• A) Hypocalcemia and hyperphosphatemia
• B) Hypercalcemia and hypophosphatemia
• C) Hypocalcemia and hypophosphatemia
• D) Hypercalcemia and hyperphosphatemia
Correct Answer: B
Rationale: PTH increases serum calcium by mobilizing it from bone and
increasing renal reabsorption. It also decreases serum phosphate by inhibiting its
reabsorption in the proximal tubule.
Q4. The anterior pituitary gland arises from which embryologic structure?
• A) Neural crest
• B) Rathke's pouch (oral ectoderm)
• C) Neural tube
• D) Mesoderm
Correct Answer: B
Rationale: The anterior pituitary (adenohypophysis) develops from Rathke's
pouch, which is an invagination of the oral ectoderm. The posterior pituitary
(neurohypophysis) develops from the neural ectoderm.
Q5. Which of the following is a characteristic of a Type I (immediate)
hypersensitivity reaction?
• A) Antibody-mediated cell destruction
• B) Immune complex deposition
, • C) Mast cell degranulation triggered by IgE cross-linking
• D) Delayed T-cell mediated inflammation
Correct Answer: C
Rationale: Type I hypersensitivity (e.g., anaphylaxis, allergies) is an immediate
reaction involving IgE antibodies bound to mast cells and basophils, leading to
degranulation upon re-exposure to the antigen.
Q6. The inner cell mass of a blastocyst gives rise to which structures?
• A) The embryo proper (fetus)
• B) The placenta
• C) The umbilical cord
• D) The amnion
Correct Answer: A
Rationale: After implantation, the blastocyst consists of an outer trophoblast layer,
which becomes the placenta, and an inner cell mass, which develops into the
embryo proper.
Q7. A patient with a history of chronic alcoholism presents with ataxia and
nystagmus. A deficiency in which vitamin is the most likely cause?
• A) Vitamin B6 (Pyridoxine)
• B) Vitamin B1 (Thiamine)
• C) Vitamin B2 (Riboflavin)
• D) Vitamin B3 (Niacin)
Correct Answer: B
Rationale: The combination of ataxia and nystagmus are key features of
Wernicke's encephalopathy, a neurological emergency caused by a deficiency of
thiamine (Vitamin B1), often seen in the setting of chronic alcohol use.
, Q8. A 65-year-old man presents with pain in his left shoulder that worsens
when he lifts his arm overhead. Physical examination reveals weakness with
resisted abduction of the left arm. Which nerve is most likely compressed?
• A) Axillary nerve
• B) Long thoracic nerve
• C) Suprascapular nerve
• D) Musculocutaneous nerve
Correct Answer: C
Rationale: The suprascapular nerve innervates the supraspinatus (initiates
abduction) and infraspinatus (external rotation). Compression, often at the
suprascapular notch, leads to weakness in the "empty can" test and external
rotation.
Q9. Which of the following is the primary neurotransmitter released by the
preganglionic neurons of both the sympathetic and parasympathetic nervous
systems?
• A) Norepinephrine
• B) Epinephrine
• C) Acetylcholine
• D) Dopamine
Correct Answer: C
Rationale: Acetylcholine is the neurotransmitter at all autonomic ganglia
(sympathetic and parasympathetic) and at the parasympathetic postganglionic-
target organ synapse.
Q10. In glycogenolysis, which enzyme is responsible for cleaving glucose-1-
phosphate from the glycogen polymer?
• A) Glycogen synthase
• B) Glycogen phosphorylase
• C) Branching enzyme
1 Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
Section 1: Foundational Biomedical Sciences (Questions 1-20)
Q1. The primary motor cortex responsible for voluntary movement is located
in which of the following gyri?
• A) Superior temporal gyrus
• B) Precentral gyrus
• C) Postcentral gyrus
• D) Inferior frontal gyrus
Correct Answer: B
Rationale: The precentral gyrus is the location of the primary motor cortex
(Brodmann area 4), which is responsible for planning and executing voluntary
movements.
Q2. Which amino acid serves as the precursor for nitric oxide (NO) synthesis
in endothelial cells?
• A) L-Arginine
• B) L-Citrulline
• C) L-Glutamate
• D) L-Lysine
, Correct Answer: A
Rationale: The amino acid L-arginine is the substrate for nitric oxide synthase
(eNOS), which produces the vasodilator nitric oxide in the vascular endothelium.
Q3. A patient presents with a tumor that is found to be secreting excessive
parathyroid hormone (PTH). Which of the following laboratory findings
would be expected?
• A) Hypocalcemia and hyperphosphatemia
• B) Hypercalcemia and hypophosphatemia
• C) Hypocalcemia and hypophosphatemia
• D) Hypercalcemia and hyperphosphatemia
Correct Answer: B
Rationale: PTH increases serum calcium by mobilizing it from bone and
increasing renal reabsorption. It also decreases serum phosphate by inhibiting its
reabsorption in the proximal tubule.
Q4. The anterior pituitary gland arises from which embryologic structure?
• A) Neural crest
• B) Rathke's pouch (oral ectoderm)
• C) Neural tube
• D) Mesoderm
Correct Answer: B
Rationale: The anterior pituitary (adenohypophysis) develops from Rathke's
pouch, which is an invagination of the oral ectoderm. The posterior pituitary
(neurohypophysis) develops from the neural ectoderm.
Q5. Which of the following is a characteristic of a Type I (immediate)
hypersensitivity reaction?
• A) Antibody-mediated cell destruction
• B) Immune complex deposition
, • C) Mast cell degranulation triggered by IgE cross-linking
• D) Delayed T-cell mediated inflammation
Correct Answer: C
Rationale: Type I hypersensitivity (e.g., anaphylaxis, allergies) is an immediate
reaction involving IgE antibodies bound to mast cells and basophils, leading to
degranulation upon re-exposure to the antigen.
Q6. The inner cell mass of a blastocyst gives rise to which structures?
• A) The embryo proper (fetus)
• B) The placenta
• C) The umbilical cord
• D) The amnion
Correct Answer: A
Rationale: After implantation, the blastocyst consists of an outer trophoblast layer,
which becomes the placenta, and an inner cell mass, which develops into the
embryo proper.
Q7. A patient with a history of chronic alcoholism presents with ataxia and
nystagmus. A deficiency in which vitamin is the most likely cause?
• A) Vitamin B6 (Pyridoxine)
• B) Vitamin B1 (Thiamine)
• C) Vitamin B2 (Riboflavin)
• D) Vitamin B3 (Niacin)
Correct Answer: B
Rationale: The combination of ataxia and nystagmus are key features of
Wernicke's encephalopathy, a neurological emergency caused by a deficiency of
thiamine (Vitamin B1), often seen in the setting of chronic alcohol use.
, Q8. A 65-year-old man presents with pain in his left shoulder that worsens
when he lifts his arm overhead. Physical examination reveals weakness with
resisted abduction of the left arm. Which nerve is most likely compressed?
• A) Axillary nerve
• B) Long thoracic nerve
• C) Suprascapular nerve
• D) Musculocutaneous nerve
Correct Answer: C
Rationale: The suprascapular nerve innervates the supraspinatus (initiates
abduction) and infraspinatus (external rotation). Compression, often at the
suprascapular notch, leads to weakness in the "empty can" test and external
rotation.
Q9. Which of the following is the primary neurotransmitter released by the
preganglionic neurons of both the sympathetic and parasympathetic nervous
systems?
• A) Norepinephrine
• B) Epinephrine
• C) Acetylcholine
• D) Dopamine
Correct Answer: C
Rationale: Acetylcholine is the neurotransmitter at all autonomic ganglia
(sympathetic and parasympathetic) and at the parasympathetic postganglionic-
target organ synapse.
Q10. In glycogenolysis, which enzyme is responsible for cleaving glucose-1-
phosphate from the glycogen polymer?
• A) Glycogen synthase
• B) Glycogen phosphorylase
• C) Branching enzyme
