NBME COMPREHENSIVE STUDY GUIDE
2026 FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ _______________ is a superficial infection of the epidermis characterized
by hypo or hyperpigmented patches on the chest and back, which are more
conspicuous after sun exposure. What is the causal organism? How do you
treat?.
Answer: Tinea versicolor Malassezia furfurtreat with antifungals (topical
ketoconazole or selenium sulfide)
◍ Damage to the ___________ can affect both bladder contraction and
internal urethral sphincter relaxation, leading to overflow incontinence.
Answer: pelvic nerve plexuspelvic parasympathetic nerves of the pelvic
plexus function to excite and contract the detrusor muscle of the bladder via
muscarinic ACh receptors sympathetic nerves mediate relaxation of the
internal urethral sphincter via alpha 1 adrenergic receptors, leading to
normal urination
◍ What is the mechanism by which oxytocin promotes uterine muscle
contractions during labor?.
Answer: 1. oxytocin binds receptor on uterine myometrial smooth muscle
cells2. signal cascade results in activation of ligand-gated calcium channels
3. calcium influx into the uterine smooth muscle cells 4. increased
calcium-calmodulin complex activation of MLCK5. phosphorylation of
myosin light chains by MLCK6. cross-bridge formation between myosin
heads and actin = contraction
◍ How do you calculate prevalence?.
Answer: total # cases / total # people in the at-risk population
,◍ 200----------Exam Section 4: Item 50 of 50Natjonal, Board of Medical
Examinersment50. A 55-year-old man comes to the office because of a
7-year history of red, dry, itchy skin over his back and buttocks. Use of
emollients and topical corticosteroids has not improved his symptoms. He
has no other history of major medical illness. His vital signsare within
normal limits. Physical examination shows the findings in the photograph.
Laboratory studies show eosinophilia and increased serum concentrations of
IgA and Ig
E. Malignant transformation of which of the following cell types is the most
likely causeof the findings in this patient?O A) BlastocytesO B)
Eosinophilsо С) МасrophagesD) Mastoid cellsO E) MonocytesF) T
lymphocytes.
Answer: F.The early stage of mycosis fungoides, the most common form of
cutaneous T-cell lymphoma, is characterized by erythematous, wrinkled,
scaly patches. If the disease remains untreated, the patches will thicken into
plaques and then tumors. The patches classicallyinvolve areas protected
from the sun such as the axillae and buttocks. As skin biopsy can be
inconclusive early in the disease, it often takes several years for a diagnosis
of mycosis fungoides to be made. It is an indolent lymphoma and has a good
prognosis. It iscaused by the infiltration of malignant T lymphocytes into the
epidermis. Histopathologic evaluation with immunohistochemical staining
for T lymphocyte specific markers is critical to the diagnosis.Incorrect
Answers: A, B, C, D, and E.Blastocytes (Choice A) are undifferentiated
cells present early in the first stages of embryonic development. They do not
play a role in the pathogenesis of mycosis fungoides.Eosinophils (Choice B)
may be increased in primary hypereosinophilia, cutaneous eosinophilic
vasculitis (eg, eosinophilic granulomatosis with polyangiitis), and multiple
causes of eosinophilic dermatosis (eg, urticaria, drug eruptions, eczema,
atopic dermatitis). Theyare not the causative cell type in mycosis
fungoides.Macrophages (Choice C) and monocytes (Choice E) are cells of
the innate immune system that serve to phagocytose foreign proteins or
organisms and also serve as antigen-presenting cells to T-lymphocytes.
Macrophages that reside in the skin are calledLangerhans cells; malignant
, transformation of Langerhans cells causes Langerhans cell histiocytosis, not
mycosis fungoides.Mastoid cells (Choice D) describe the air-lined spaces
contained within the mastoid region of the temporal bone and are not
involved in skin rashes. A similarly named cell, the mast cell, is increased in
mastocy
◍ Vitamin C (ascorbic acid) is an antioxidant and coenzyme in the synthesis of
_____________ via what enzyme?.
Answer: collagen prolyl hydroxylasecan lead to scurvy due to impaired
collagen synthesis--> weakness of blood vessel walls due to collagen and
connective tissue deficiency- swollen bleeding gums- easy bleeding and
bruising- petechiae- impaired wound healing- fragile curly hair*should not
be confused with hemophilia
◍ What explains why deoxygenated blood can carry more carbon dioxide for a
given PCO2 than oxygenated blood?.
Answer: deoxyhemoglobin is a better buffer for hydrogen ions than
oxyhemoglobinthis is called the HALDANE effectwhen hemoglobin
unloads oxygen in the tissues, it is more accepting of hydrogen ions. the
cytosolic increase in PH from the removal of hydrogen ions that are now
bound to hemoglobin favors the formation of bicarbonate from carbon
dioxide and water. bicarbonate is a highly soluble form of carbon dioxide
◍ Presents with low blood pressure, increased heart rate, decreased jugular
venous distension, and dry mucous membranes..
Answer: intravascular hypovolemia
◍ 1----------Exam Section 1: Item 2 of 50National, Board of Medical
ExaminersComprehensive Basic Science Self-Assessment2. Free purine and
pyrimidine bases are reutilized in normal metabolism. In children with
Lesch-Nyhan syndrome who have intellectual disability, poor muscle
coordination, and self-mutilation tendencies, there is a defect in the salvage
of which of the followingpairs of bases?A) Adenine and thymineB) Guanine
and hypoxanthineC) Guanine and uric acidD) Uracil and cytosineE)
Xanthine and hypoxanthine.
, Answer: B.Lesch-Nyhan syndrome presents with intellectual disability,
aggressive behavior, self-mutilation, gout, and dystonia. The disorder is due
to inactivating mutations of hypoxanthine-guanine
phosphoribosyltransferase (HGPRT), a key enzyme in the purine
salvagepathway, and is inherited in an X-linked recessive fashion. HGPRT
catalyzes the conversion of guanine to guanosine monophosphate and
hypoxanthine to inosine monophosphate. Patients with deficient activity of
HGPRT are unable to salvage guanine andhypoxanthine and develop
resultant increased levels of xanthine and uric acid. Hyperuricemia in
Lesch-Nyhan syndrome is treated with xanthine oxidase inhibitors, such as
allopurinol or febuxostat, in order to reduce the synthesis of uric
acid.Incorrect Answers: A, C, D and E.Adenine and thymine (Choice A) are
purine and pyrimidine bases, respectively. Purine and pyrimidine salvage
are handled through two distinct pathways that are not commonly involved
in a single disease process.Guanine and uric acid (Choice C) accumulation
may occur as part of Lesch-Nyhan syndrome, however, the accumulation of
uric acid is also secondary to accumulation of hypoxanthine. Choice B more
accurately describes defective salvage of guanine andhypoxanthine as the
fundamental effect of HGPRT dysfunction. The accumulation of uric acid is
secondary.Uracil and cytosine (Choice D) are pyrimidine nucleotides.
Pyrimidine salvage is not affected by mutations of HGPRT.Defects of
xanthine and hypoxanthine (Choice E) metabolism may result from defects
in HGPRT. However, HGPRT dysfunction results in impaired hypoxanthine
salvage with resultant excessive production of xanthine, rather than
impaired xanthine salvage.Educational Objective: Lesch-Nyhan syndrome
presents with intellectual disability, aggressive behavior, self-mutilation,
gout, and dyst
◍ Lesions of the __________ horn of the spinal cord can interrupt the
sympathetic nerve supply to the ipsilateral face and eye and cause Horner
syndrome.
Answer: intermediate horn, between spinal cord levels C8 and T1aka
ciliospinal center of Budge
2026 FULL QUESTIONS AND SOLUTIONS
GRADED A+
◍ _______________ is a superficial infection of the epidermis characterized
by hypo or hyperpigmented patches on the chest and back, which are more
conspicuous after sun exposure. What is the causal organism? How do you
treat?.
Answer: Tinea versicolor Malassezia furfurtreat with antifungals (topical
ketoconazole or selenium sulfide)
◍ Damage to the ___________ can affect both bladder contraction and
internal urethral sphincter relaxation, leading to overflow incontinence.
Answer: pelvic nerve plexuspelvic parasympathetic nerves of the pelvic
plexus function to excite and contract the detrusor muscle of the bladder via
muscarinic ACh receptors sympathetic nerves mediate relaxation of the
internal urethral sphincter via alpha 1 adrenergic receptors, leading to
normal urination
◍ What is the mechanism by which oxytocin promotes uterine muscle
contractions during labor?.
Answer: 1. oxytocin binds receptor on uterine myometrial smooth muscle
cells2. signal cascade results in activation of ligand-gated calcium channels
3. calcium influx into the uterine smooth muscle cells 4. increased
calcium-calmodulin complex activation of MLCK5. phosphorylation of
myosin light chains by MLCK6. cross-bridge formation between myosin
heads and actin = contraction
◍ How do you calculate prevalence?.
Answer: total # cases / total # people in the at-risk population
,◍ 200----------Exam Section 4: Item 50 of 50Natjonal, Board of Medical
Examinersment50. A 55-year-old man comes to the office because of a
7-year history of red, dry, itchy skin over his back and buttocks. Use of
emollients and topical corticosteroids has not improved his symptoms. He
has no other history of major medical illness. His vital signsare within
normal limits. Physical examination shows the findings in the photograph.
Laboratory studies show eosinophilia and increased serum concentrations of
IgA and Ig
E. Malignant transformation of which of the following cell types is the most
likely causeof the findings in this patient?O A) BlastocytesO B)
Eosinophilsо С) МасrophagesD) Mastoid cellsO E) MonocytesF) T
lymphocytes.
Answer: F.The early stage of mycosis fungoides, the most common form of
cutaneous T-cell lymphoma, is characterized by erythematous, wrinkled,
scaly patches. If the disease remains untreated, the patches will thicken into
plaques and then tumors. The patches classicallyinvolve areas protected
from the sun such as the axillae and buttocks. As skin biopsy can be
inconclusive early in the disease, it often takes several years for a diagnosis
of mycosis fungoides to be made. It is an indolent lymphoma and has a good
prognosis. It iscaused by the infiltration of malignant T lymphocytes into the
epidermis. Histopathologic evaluation with immunohistochemical staining
for T lymphocyte specific markers is critical to the diagnosis.Incorrect
Answers: A, B, C, D, and E.Blastocytes (Choice A) are undifferentiated
cells present early in the first stages of embryonic development. They do not
play a role in the pathogenesis of mycosis fungoides.Eosinophils (Choice B)
may be increased in primary hypereosinophilia, cutaneous eosinophilic
vasculitis (eg, eosinophilic granulomatosis with polyangiitis), and multiple
causes of eosinophilic dermatosis (eg, urticaria, drug eruptions, eczema,
atopic dermatitis). Theyare not the causative cell type in mycosis
fungoides.Macrophages (Choice C) and monocytes (Choice E) are cells of
the innate immune system that serve to phagocytose foreign proteins or
organisms and also serve as antigen-presenting cells to T-lymphocytes.
Macrophages that reside in the skin are calledLangerhans cells; malignant
, transformation of Langerhans cells causes Langerhans cell histiocytosis, not
mycosis fungoides.Mastoid cells (Choice D) describe the air-lined spaces
contained within the mastoid region of the temporal bone and are not
involved in skin rashes. A similarly named cell, the mast cell, is increased in
mastocy
◍ Vitamin C (ascorbic acid) is an antioxidant and coenzyme in the synthesis of
_____________ via what enzyme?.
Answer: collagen prolyl hydroxylasecan lead to scurvy due to impaired
collagen synthesis--> weakness of blood vessel walls due to collagen and
connective tissue deficiency- swollen bleeding gums- easy bleeding and
bruising- petechiae- impaired wound healing- fragile curly hair*should not
be confused with hemophilia
◍ What explains why deoxygenated blood can carry more carbon dioxide for a
given PCO2 than oxygenated blood?.
Answer: deoxyhemoglobin is a better buffer for hydrogen ions than
oxyhemoglobinthis is called the HALDANE effectwhen hemoglobin
unloads oxygen in the tissues, it is more accepting of hydrogen ions. the
cytosolic increase in PH from the removal of hydrogen ions that are now
bound to hemoglobin favors the formation of bicarbonate from carbon
dioxide and water. bicarbonate is a highly soluble form of carbon dioxide
◍ Presents with low blood pressure, increased heart rate, decreased jugular
venous distension, and dry mucous membranes..
Answer: intravascular hypovolemia
◍ 1----------Exam Section 1: Item 2 of 50National, Board of Medical
ExaminersComprehensive Basic Science Self-Assessment2. Free purine and
pyrimidine bases are reutilized in normal metabolism. In children with
Lesch-Nyhan syndrome who have intellectual disability, poor muscle
coordination, and self-mutilation tendencies, there is a defect in the salvage
of which of the followingpairs of bases?A) Adenine and thymineB) Guanine
and hypoxanthineC) Guanine and uric acidD) Uracil and cytosineE)
Xanthine and hypoxanthine.
, Answer: B.Lesch-Nyhan syndrome presents with intellectual disability,
aggressive behavior, self-mutilation, gout, and dystonia. The disorder is due
to inactivating mutations of hypoxanthine-guanine
phosphoribosyltransferase (HGPRT), a key enzyme in the purine
salvagepathway, and is inherited in an X-linked recessive fashion. HGPRT
catalyzes the conversion of guanine to guanosine monophosphate and
hypoxanthine to inosine monophosphate. Patients with deficient activity of
HGPRT are unable to salvage guanine andhypoxanthine and develop
resultant increased levels of xanthine and uric acid. Hyperuricemia in
Lesch-Nyhan syndrome is treated with xanthine oxidase inhibitors, such as
allopurinol or febuxostat, in order to reduce the synthesis of uric
acid.Incorrect Answers: A, C, D and E.Adenine and thymine (Choice A) are
purine and pyrimidine bases, respectively. Purine and pyrimidine salvage
are handled through two distinct pathways that are not commonly involved
in a single disease process.Guanine and uric acid (Choice C) accumulation
may occur as part of Lesch-Nyhan syndrome, however, the accumulation of
uric acid is also secondary to accumulation of hypoxanthine. Choice B more
accurately describes defective salvage of guanine andhypoxanthine as the
fundamental effect of HGPRT dysfunction. The accumulation of uric acid is
secondary.Uracil and cytosine (Choice D) are pyrimidine nucleotides.
Pyrimidine salvage is not affected by mutations of HGPRT.Defects of
xanthine and hypoxanthine (Choice E) metabolism may result from defects
in HGPRT. However, HGPRT dysfunction results in impaired hypoxanthine
salvage with resultant excessive production of xanthine, rather than
impaired xanthine salvage.Educational Objective: Lesch-Nyhan syndrome
presents with intellectual disability, aggressive behavior, self-mutilation,
gout, and dyst
◍ Lesions of the __________ horn of the spinal cord can interrupt the
sympathetic nerve supply to the ipsilateral face and eye and cause Horner
syndrome.
Answer: intermediate horn, between spinal cord levels C8 and T1aka
ciliospinal center of Budge
