COMPREHENSIVE OSTEOPATHIC
MEDICAL LICENSING EXAMINATION OF
THE UNITED STATES (COMLEX-USA)
LEVEL 1 PRACTICE EXAM QUESTIONS
AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
| INSTANT DOWNLOAD PDF
1. Which structure passes through the foramen ovale?
A. Middle meningeal artery
B. Mandibular nerve
C. Optic nerve
D. Internal carotid artery
Answer: B. Mandibular nerve
Rationale: The foramen ovale transmits the mandibular division (V3) of the
trigeminal nerve, along with accessory meningeal artery and lesser petrosal
nerve. Other options pass through different foramina (e.g., middle
meningeal artery via foramen spinosum, optic nerve via optic canal).
2. A patient presents with hypercalcemia. Which hormone is most likely
elevated?
A. Calcitonin
B. Parathyroid hormone
C. Insulin
D. Cortisol
Answer: B. Parathyroid hormone
Rationale: Parathyroid hormone increases serum calcium by stimulating
, osteoclast activity, renal calcium reabsorption, and vitamin D activation.
Hypercalcemia is commonly associated with hyperparathyroidism.
3. Which type of epithelium lines the trachea?
A. Stratified squamous
B. Simple cuboidal
C. Pseudostratified ciliated columnar
D. Transitional
Answer: C. Pseudostratified ciliated columnar
Rationale: The trachea is lined by respiratory epithelium, which is
pseudostratified ciliated columnar with goblet cells that help trap and move
particles upward.
4. What is the primary neurotransmitter at the neuromuscular junction?
A. Dopamine
B. Acetylcholine
C. Serotonin
D. GABA
Answer: B. Acetylcholine
Rationale: Acetylcholine is released from motor neurons and binds nicotinic
receptors on muscle cells, causing depolarization and contraction.
5. Which vitamin deficiency causes scurvy?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Answer: B. Vitamin C
Rationale: Vitamin C is essential for collagen synthesis. Deficiency leads to
weak connective tissue, bleeding gums, and poor wound healing.
6. Which artery supplies the lateral aspect of the forearm?
A. Radial artery
B. Ulnar artery
C. Brachial artery
, D. Axillary artery
Answer: A. Radial artery
Rationale: The radial artery runs along the lateral (thumb) side of the
forearm and supplies blood to that region.
7. What is the function of the loop of Henle?
A. Filtration
B. Reabsorption of glucose
C. Concentration of urine
D. Secretion of potassium
Answer: C. Concentration of urine
Rationale: The loop of Henle creates a concentration gradient in the
medulla, allowing water reabsorption and urine concentration.
8. Which cranial nerve controls facial expression?
A. Trigeminal
B. Facial
C. Glossopharyngeal
D. Vagus
Answer: B. Facial
Rationale: The facial nerve (CN VII) innervates muscles of facial expression.
9. Which part of the brain regulates balance?
A. Cerebrum
B. Cerebellum
C. Medulla
D. Hypothalamus
Answer: B. Cerebellum
Rationale: The cerebellum coordinates movement, balance, and posture.
10.Which hormone regulates circadian rhythm?
A. Melatonin
B. Thyroxine
C. Aldosterone
D. Prolactin
MEDICAL LICENSING EXAMINATION OF
THE UNITED STATES (COMLEX-USA)
LEVEL 1 PRACTICE EXAM QUESTIONS
AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
| INSTANT DOWNLOAD PDF
1. Which structure passes through the foramen ovale?
A. Middle meningeal artery
B. Mandibular nerve
C. Optic nerve
D. Internal carotid artery
Answer: B. Mandibular nerve
Rationale: The foramen ovale transmits the mandibular division (V3) of the
trigeminal nerve, along with accessory meningeal artery and lesser petrosal
nerve. Other options pass through different foramina (e.g., middle
meningeal artery via foramen spinosum, optic nerve via optic canal).
2. A patient presents with hypercalcemia. Which hormone is most likely
elevated?
A. Calcitonin
B. Parathyroid hormone
C. Insulin
D. Cortisol
Answer: B. Parathyroid hormone
Rationale: Parathyroid hormone increases serum calcium by stimulating
, osteoclast activity, renal calcium reabsorption, and vitamin D activation.
Hypercalcemia is commonly associated with hyperparathyroidism.
3. Which type of epithelium lines the trachea?
A. Stratified squamous
B. Simple cuboidal
C. Pseudostratified ciliated columnar
D. Transitional
Answer: C. Pseudostratified ciliated columnar
Rationale: The trachea is lined by respiratory epithelium, which is
pseudostratified ciliated columnar with goblet cells that help trap and move
particles upward.
4. What is the primary neurotransmitter at the neuromuscular junction?
A. Dopamine
B. Acetylcholine
C. Serotonin
D. GABA
Answer: B. Acetylcholine
Rationale: Acetylcholine is released from motor neurons and binds nicotinic
receptors on muscle cells, causing depolarization and contraction.
5. Which vitamin deficiency causes scurvy?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Answer: B. Vitamin C
Rationale: Vitamin C is essential for collagen synthesis. Deficiency leads to
weak connective tissue, bleeding gums, and poor wound healing.
6. Which artery supplies the lateral aspect of the forearm?
A. Radial artery
B. Ulnar artery
C. Brachial artery
, D. Axillary artery
Answer: A. Radial artery
Rationale: The radial artery runs along the lateral (thumb) side of the
forearm and supplies blood to that region.
7. What is the function of the loop of Henle?
A. Filtration
B. Reabsorption of glucose
C. Concentration of urine
D. Secretion of potassium
Answer: C. Concentration of urine
Rationale: The loop of Henle creates a concentration gradient in the
medulla, allowing water reabsorption and urine concentration.
8. Which cranial nerve controls facial expression?
A. Trigeminal
B. Facial
C. Glossopharyngeal
D. Vagus
Answer: B. Facial
Rationale: The facial nerve (CN VII) innervates muscles of facial expression.
9. Which part of the brain regulates balance?
A. Cerebrum
B. Cerebellum
C. Medulla
D. Hypothalamus
Answer: B. Cerebellum
Rationale: The cerebellum coordinates movement, balance, and posture.
10.Which hormone regulates circadian rhythm?
A. Melatonin
B. Thyroxine
C. Aldosterone
D. Prolactin
