3/17/25, 5:49 PM NBME 30
NBME 30 (CBSE) REAL EXAM 210 QUESTIONS AND ANSWERS
LATEST MEDICAL EXAMINATION \\NATIONAL BOARD OF
MEDICAL EXAMINERS ® COMPREHENSIVE BASIC SCIENCE
A.
Abnormal neural crest development leads to
Waardenburg syndrome. Waardenburg syndrome is a
1
syndrome of patchy depigmentation of the skin, hair,
Exam Section 1: Item 1 of 50
irises, and cochlear dysfunction that primarily
National Board of Medical
illustrates an autosomal dominant inheritance pattern.
Examiners® Comprehensive
Because of
Basic Science Self-
genetic mutations of genes encoding transcription
Assessment
factors, neural crest cells do not properly differentiate
1. Shortly after delivery, a
into melanoblasts (melanocyte precursors), or
full-term male newborn is
melanoblasts do not migrate to their appropriate
found to have black hair
location. Patients typically have a white forelock and
with a white forelock. His
eyelashes,
mother, a brunette, also has
depigmented skin patches, iridic heterochromia, and
a white forelock and wears
sensorineural deafness. The eyes may also be laterally
hearing aids. Physical
displaced. The clinical diagnosis may be confirmed with
examination shows
genetic testing. Treatment includes audiologic
heterochromia of irides.
evaluation and genetic consultation. Incorrect Answers:
Otoacoustic emissions
B, C, D, E, and F.
testing and
An abnormality of connexins (Choice B) would lead to
brain stem auditory evoked
abnormal formation of the plasma membrane channels
responses show bilateral
of diverse cell types. Different combinations of
sensorineural hearing loss.
sensorineural hearing loss, ichthyosis, alopecia, and
Which of the following is the
peripheral neuropathy may occur. Depigmentation
most likely cause of the
would be atypical.
findings in this patient?
Deficiency of homogentisic acid oxidase activity
A) Abnormal neural crest
development (Choice C) would lead to decreased metabolism of the
B) Abnormality of connexins amino acids phenylalanine and tyrosine, which instead
C) Deficiency of
degrade into homogentisic acid. Homogentisic acid
homogentisic acid oxidase accumulates in the skin and joints, causing increased
activity
/ 1/397
,3/17/25, 5:49 PM NBME 30
D) Deficiency of tyrosinase pigmentation and arthritis, respectively.
activity
E) Failure of Depigmentation would be atypical. Deficiency of
internalization of tyrosinase activity (Choice D) occurs in oculocutaneous
melanin granules by albinism, which presents with uniformly
keratinocytes hypopigmented hair and skin (versus the patchy
F) Failure of melanosome depigmentation of Waardenburg syndrome) and eye
transportation along abnormalities (eg, iris hypopigmentation, refractive
dendrites errors, nystagmus). In tyrosinase deficiency,
melanocytes are unable to synthesize melanin from the
amino acid tyrosine. Iridic heterochromia and
sensorineural deafnes
/ 2/397
,3/17/25, 5:49 PM NBME 30
B.
Glucose-dependent insulinotropic peptide (GIP) is
secreted by K cells in the duodenum and jejunum and
2
functions to decrease gastric acid production and
Exam Section 1: Item 2 of 50
stimulate insulin release from the pancreas. Its
National Board of Medical
secretion is promoted by the presence of fatty acids,
Examiners® Comprehensive
amino
Basic Science Self-
acids, and intestinal glucose. While serum glucose also
Assessment
stimulates insulin secretion by the pancreas, the effect
2. During an experiment, a
of intraluminal glucose on GIP and subsequent insulin
solution of mixed fatty
secretion leads to increased concentrations of insulin
acids is injected into the
compared to parenteral glucose
duodenum of an
administration. Insulin promotes peripheral tissue uptake
experimental animal. Under
of glucose, glycolysis, glycogen synthesis, protein
these conditions, the
synthesis, and fatty acid synthesis, resulting in decreased
clearance rate of an
glucose concentration in the serum.
intravenous glucose load
Incorrect Answers: A, C, D, and E.
from the circulation is
Gastrin (Choice A) is produced by G cells in the gastric
doubled. In contrast, an
antrum and stimulates parietal cells within the gastric
injection of an equal
body to produce hydrochloric acid. Gastric acid has no
volume amount of 0.9%
effect on serum glucose concentration.
saline into the duodenum has
Motilin (Choice C) is secreted by the small intestine
much less effect on the
and stimulates intestinal peristalsis. Motilin
plasma clearance rate of
receptors are targeted by erythromycin and
glucose. These findings are
metoclopramide, used therapeutically in
most likely caused by the
gastroparesis.
secretion of which of the
Secretin (Choice D) is produced by duodenal S cells. It
following hormones?
promotes the release of bicarbonate-rich pancreatic
A) Gastrin
secretions and bile and inhibits gastric acid production.
B) Glucose-dependent
Somatostatin (Choice E) is a regulatory peptide
insulinotropic peptide
C) Motilin secreted by D cells of the pancreas and
D) Secretin gastrointestinal mucosa that inhibits gastric acid and
E) Somatostatin pepsinogen secretion, gallbladder contraction, and
insulin and glucagon release. Somatostatin would have
an indirect
effect on glucose through counterregulatory action of
both insulin and glucagon. Educational Objective:
/ 3/397
, 3/17/25, 5:49 PM NBME 30
Glucose-dependent insulinotropic peptide (GIP) is
secreted by K cells in the duodenum and jejunum, and
it functions to decrease gastric acid production and
/ 4/397
NBME 30 (CBSE) REAL EXAM 210 QUESTIONS AND ANSWERS
LATEST MEDICAL EXAMINATION \\NATIONAL BOARD OF
MEDICAL EXAMINERS ® COMPREHENSIVE BASIC SCIENCE
A.
Abnormal neural crest development leads to
Waardenburg syndrome. Waardenburg syndrome is a
1
syndrome of patchy depigmentation of the skin, hair,
Exam Section 1: Item 1 of 50
irises, and cochlear dysfunction that primarily
National Board of Medical
illustrates an autosomal dominant inheritance pattern.
Examiners® Comprehensive
Because of
Basic Science Self-
genetic mutations of genes encoding transcription
Assessment
factors, neural crest cells do not properly differentiate
1. Shortly after delivery, a
into melanoblasts (melanocyte precursors), or
full-term male newborn is
melanoblasts do not migrate to their appropriate
found to have black hair
location. Patients typically have a white forelock and
with a white forelock. His
eyelashes,
mother, a brunette, also has
depigmented skin patches, iridic heterochromia, and
a white forelock and wears
sensorineural deafness. The eyes may also be laterally
hearing aids. Physical
displaced. The clinical diagnosis may be confirmed with
examination shows
genetic testing. Treatment includes audiologic
heterochromia of irides.
evaluation and genetic consultation. Incorrect Answers:
Otoacoustic emissions
B, C, D, E, and F.
testing and
An abnormality of connexins (Choice B) would lead to
brain stem auditory evoked
abnormal formation of the plasma membrane channels
responses show bilateral
of diverse cell types. Different combinations of
sensorineural hearing loss.
sensorineural hearing loss, ichthyosis, alopecia, and
Which of the following is the
peripheral neuropathy may occur. Depigmentation
most likely cause of the
would be atypical.
findings in this patient?
Deficiency of homogentisic acid oxidase activity
A) Abnormal neural crest
development (Choice C) would lead to decreased metabolism of the
B) Abnormality of connexins amino acids phenylalanine and tyrosine, which instead
C) Deficiency of
degrade into homogentisic acid. Homogentisic acid
homogentisic acid oxidase accumulates in the skin and joints, causing increased
activity
/ 1/397
,3/17/25, 5:49 PM NBME 30
D) Deficiency of tyrosinase pigmentation and arthritis, respectively.
activity
E) Failure of Depigmentation would be atypical. Deficiency of
internalization of tyrosinase activity (Choice D) occurs in oculocutaneous
melanin granules by albinism, which presents with uniformly
keratinocytes hypopigmented hair and skin (versus the patchy
F) Failure of melanosome depigmentation of Waardenburg syndrome) and eye
transportation along abnormalities (eg, iris hypopigmentation, refractive
dendrites errors, nystagmus). In tyrosinase deficiency,
melanocytes are unable to synthesize melanin from the
amino acid tyrosine. Iridic heterochromia and
sensorineural deafnes
/ 2/397
,3/17/25, 5:49 PM NBME 30
B.
Glucose-dependent insulinotropic peptide (GIP) is
secreted by K cells in the duodenum and jejunum and
2
functions to decrease gastric acid production and
Exam Section 1: Item 2 of 50
stimulate insulin release from the pancreas. Its
National Board of Medical
secretion is promoted by the presence of fatty acids,
Examiners® Comprehensive
amino
Basic Science Self-
acids, and intestinal glucose. While serum glucose also
Assessment
stimulates insulin secretion by the pancreas, the effect
2. During an experiment, a
of intraluminal glucose on GIP and subsequent insulin
solution of mixed fatty
secretion leads to increased concentrations of insulin
acids is injected into the
compared to parenteral glucose
duodenum of an
administration. Insulin promotes peripheral tissue uptake
experimental animal. Under
of glucose, glycolysis, glycogen synthesis, protein
these conditions, the
synthesis, and fatty acid synthesis, resulting in decreased
clearance rate of an
glucose concentration in the serum.
intravenous glucose load
Incorrect Answers: A, C, D, and E.
from the circulation is
Gastrin (Choice A) is produced by G cells in the gastric
doubled. In contrast, an
antrum and stimulates parietal cells within the gastric
injection of an equal
body to produce hydrochloric acid. Gastric acid has no
volume amount of 0.9%
effect on serum glucose concentration.
saline into the duodenum has
Motilin (Choice C) is secreted by the small intestine
much less effect on the
and stimulates intestinal peristalsis. Motilin
plasma clearance rate of
receptors are targeted by erythromycin and
glucose. These findings are
metoclopramide, used therapeutically in
most likely caused by the
gastroparesis.
secretion of which of the
Secretin (Choice D) is produced by duodenal S cells. It
following hormones?
promotes the release of bicarbonate-rich pancreatic
A) Gastrin
secretions and bile and inhibits gastric acid production.
B) Glucose-dependent
Somatostatin (Choice E) is a regulatory peptide
insulinotropic peptide
C) Motilin secreted by D cells of the pancreas and
D) Secretin gastrointestinal mucosa that inhibits gastric acid and
E) Somatostatin pepsinogen secretion, gallbladder contraction, and
insulin and glucagon release. Somatostatin would have
an indirect
effect on glucose through counterregulatory action of
both insulin and glucagon. Educational Objective:
/ 3/397
, 3/17/25, 5:49 PM NBME 30
Glucose-dependent insulinotropic peptide (GIP) is
secreted by K cells in the duodenum and jejunum, and
it functions to decrease gastric acid production and
/ 4/397
