NBME TEST PAPER 2026 COMPLETE
QUESTIONS WITH VERIFIED ANSWERS
⫸2
Exam Section 1: Item 2 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
2. A 65-year-old man comes to the emergency department because of a
1-week history of blood in his sputum. A mass is found on a radiograph.
Bronchoscopy is planned. In order to pass the
bronchoscope through the oropharynx to the lungs without eliciting a
gag reflex, the pharynx is anesthetized. The afferent limb of the reflex is
most likely to be blocked by anesthesia to which
of the following cranial nerves?
A) Trigeminal
B) Facial
C) Glossopharyngeal
D) Vagus
E) Hypoglossal Answer: C.
The glossopharyngeal nerve (cranial nerve IX) contains somatic afferent
fibers that control the sensation of the palate and upper pharynx,
providing afferent information for the gag reflex. The
efferent nerve for the gag reflex is the vagus nerve, which innervates the
soft palate and pharyngeal muscles to control gagging and swallowing.
In addition to its role in the gag reflex, the
,glossopharyngeal nerve contains other afferent and efferent nerve fibers.
Components of the glossopharyngeal nerve include general visceral
afferent fibers (carotid body and sinus chemo- and
baroreceptors), special sensory fibers (taste from posterior third of the
tongue), general visceral efferent fibers (parasympathetic innervation of
the parotid gland), and special visceral efferent
fibers (stylopharyngeus muscle). Lesions of the glossopharyngeal nerve
lead to impaired sensation and taste in the posterior third of the tongue,
impaired sensation of the palate and pharynx,
parotid gland dysfunction, difficulty swallowing, and an absent gag
reflex.
Incorrect Answers: A, B, D, and E.
The trigeminal nerve (Choice A), or cranial nerve V, provides somatic
sensory innervation to the face and scalp. The mandibular nerve (the V3
branch of the trigeminal nerve) additionally controls
the muscles of mastication and mediates pain and temperature sensation
in the anterior two-thirds of the tongue. The trigeminal nerve does not
innervate the pharynx.
The facial nerve (Choice B), or cranial nerve VII, contains afferent and
efferent fibers that carry somatic and visceral information. Motor axons
innervate the muscles of facial expression and the
stapedius muscle, while sensory axons innervate the outer ear and
mediate taste sensation from the anterior two-thirds of the tongue. The
facial nerve does not innervate the pharynx.
The vagus nerve (Choice D),
⫸3
,Exam Section 1: Item 3 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
3. A 62-year-old man with a 4-year history of chronic angina pectoris
comes to the emergency department because of severe chest and left
shoulder pain. Physical examination shows
bradycardia. An ECG shows ST-segment elevation in leads II, III, and
aVF. Occlusion of blood flow in which of the following arteries is the
most likely cause of the findings in this patient?
A) Anterior interventricular (left anterior descending)
B) Circumflex
C) Left coronary
D) Right coronary Answer: D.
The right coronary artery originates from the right aortic sinus and
primarily provides blood flow to the right ventricle, right atrium,
sinoatrial (SA) node, and atrioventricular (AV) node, and in a
right-dominant circulation (-85% of patients), it provides a majority of
the blood supply to the inferior heart through the posterior descending
artery. Occlusion of the right coronary artery can
result in infarction of myocardial tissue along the inferior portion of the
heart, which leads to ST-segment changes in the inferior ECG leads II,
III, and aVF. Impaired perfusion to the SA and AV
nodes can also result in bradycardia or heart block. The patient requires
admission to the hospital and emergent cardiac catheterization for
revascularization or consideration of thrombolytics if
not close to a center capable of percutaneous coronary intervention.
Incorrect Answers: A, B, and C.
, The anterior interventricular (left anterior descending) (Choice A) artery
branches from the left main coronary artery and provides perfusion to
the anterior portion of the interventricular septum,
the anterior left ventricle, and the anterolateral papillary muscle.
Infarction of this territory may present with ST-segment changes in the
precordial ECCG leads.
The circumflex (Choice B) artery originates from the left main coronary
artery and primarily provides perfusion to the lateral and posterior walls
of the left ventricle, the anterolateral papillary
muscle, and some blood flow to the AV node. It does not provide
perfusion to the inferior heart unless the patient demonstrates a left-
dominant circulation (~8% of patients). Infarction of this
territory may result in ST-segment changes in the lateral, posterior,
and/or inferior ECG leads.
The left coronary (Choice C), or left main coronary, artery arises from
the left aortic sinus and branches
⫸4
Exam Section 1: Item 4 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
4. Cholestyramine prevents the reabsorption of bile acids from the lumen
of the intestine. This decreases serum cholesterol concentrations by
which of the following mechanisms?
A) Activating lecithin-cholesterol acyltransferase (LCAT)
B) Decreasing VLDL production
OC) Inhibiting hepatic cholesterol synthesis
QUESTIONS WITH VERIFIED ANSWERS
⫸2
Exam Section 1: Item 2 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
2. A 65-year-old man comes to the emergency department because of a
1-week history of blood in his sputum. A mass is found on a radiograph.
Bronchoscopy is planned. In order to pass the
bronchoscope through the oropharynx to the lungs without eliciting a
gag reflex, the pharynx is anesthetized. The afferent limb of the reflex is
most likely to be blocked by anesthesia to which
of the following cranial nerves?
A) Trigeminal
B) Facial
C) Glossopharyngeal
D) Vagus
E) Hypoglossal Answer: C.
The glossopharyngeal nerve (cranial nerve IX) contains somatic afferent
fibers that control the sensation of the palate and upper pharynx,
providing afferent information for the gag reflex. The
efferent nerve for the gag reflex is the vagus nerve, which innervates the
soft palate and pharyngeal muscles to control gagging and swallowing.
In addition to its role in the gag reflex, the
,glossopharyngeal nerve contains other afferent and efferent nerve fibers.
Components of the glossopharyngeal nerve include general visceral
afferent fibers (carotid body and sinus chemo- and
baroreceptors), special sensory fibers (taste from posterior third of the
tongue), general visceral efferent fibers (parasympathetic innervation of
the parotid gland), and special visceral efferent
fibers (stylopharyngeus muscle). Lesions of the glossopharyngeal nerve
lead to impaired sensation and taste in the posterior third of the tongue,
impaired sensation of the palate and pharynx,
parotid gland dysfunction, difficulty swallowing, and an absent gag
reflex.
Incorrect Answers: A, B, D, and E.
The trigeminal nerve (Choice A), or cranial nerve V, provides somatic
sensory innervation to the face and scalp. The mandibular nerve (the V3
branch of the trigeminal nerve) additionally controls
the muscles of mastication and mediates pain and temperature sensation
in the anterior two-thirds of the tongue. The trigeminal nerve does not
innervate the pharynx.
The facial nerve (Choice B), or cranial nerve VII, contains afferent and
efferent fibers that carry somatic and visceral information. Motor axons
innervate the muscles of facial expression and the
stapedius muscle, while sensory axons innervate the outer ear and
mediate taste sensation from the anterior two-thirds of the tongue. The
facial nerve does not innervate the pharynx.
The vagus nerve (Choice D),
⫸3
,Exam Section 1: Item 3 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
3. A 62-year-old man with a 4-year history of chronic angina pectoris
comes to the emergency department because of severe chest and left
shoulder pain. Physical examination shows
bradycardia. An ECG shows ST-segment elevation in leads II, III, and
aVF. Occlusion of blood flow in which of the following arteries is the
most likely cause of the findings in this patient?
A) Anterior interventricular (left anterior descending)
B) Circumflex
C) Left coronary
D) Right coronary Answer: D.
The right coronary artery originates from the right aortic sinus and
primarily provides blood flow to the right ventricle, right atrium,
sinoatrial (SA) node, and atrioventricular (AV) node, and in a
right-dominant circulation (-85% of patients), it provides a majority of
the blood supply to the inferior heart through the posterior descending
artery. Occlusion of the right coronary artery can
result in infarction of myocardial tissue along the inferior portion of the
heart, which leads to ST-segment changes in the inferior ECG leads II,
III, and aVF. Impaired perfusion to the SA and AV
nodes can also result in bradycardia or heart block. The patient requires
admission to the hospital and emergent cardiac catheterization for
revascularization or consideration of thrombolytics if
not close to a center capable of percutaneous coronary intervention.
Incorrect Answers: A, B, and C.
, The anterior interventricular (left anterior descending) (Choice A) artery
branches from the left main coronary artery and provides perfusion to
the anterior portion of the interventricular septum,
the anterior left ventricle, and the anterolateral papillary muscle.
Infarction of this territory may present with ST-segment changes in the
precordial ECCG leads.
The circumflex (Choice B) artery originates from the left main coronary
artery and primarily provides perfusion to the lateral and posterior walls
of the left ventricle, the anterolateral papillary
muscle, and some blood flow to the AV node. It does not provide
perfusion to the inferior heart unless the patient demonstrates a left-
dominant circulation (~8% of patients). Infarction of this
territory may result in ST-segment changes in the lateral, posterior,
and/or inferior ECG leads.
The left coronary (Choice C), or left main coronary, artery arises from
the left aortic sinus and branches
⫸4
Exam Section 1: Item 4 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
4. Cholestyramine prevents the reabsorption of bile acids from the lumen
of the intestine. This decreases serum cholesterol concentrations by
which of the following mechanisms?
A) Activating lecithin-cholesterol acyltransferase (LCAT)
B) Decreasing VLDL production
OC) Inhibiting hepatic cholesterol synthesis
