Page 1 of 152
Exam (elaborations) NEURO DEVELOPMENT
EXAM REVIEW WITH CORRECT AND WELL
ILLUSTRATED ANSWERS
Q1. What does the neural plate give rise to during the third
week of gestation?
A. Neural crest cells only
B. Neural tube and neural crest
C. Notochord
D. Somites
✅ Answer: B. Neural tube and neural crest
Rationale: The neural plate invaginates to form the neural
groove, then fuses to create the neural tube (CNS) and neural
crest (PNS).
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Q2. By which gestational day does the anterior neuropore
close?
A. Day 18
B. Day 24
C. Day 28
D. Day 32
✅ Answer: C. Day 28
Rationale: Anterior neuropore closes around day 24–26
(commonly day 28 in some texts). Failure causes anencephaly.
Q3. Which structure induces neural plate formation?
A. Surface ectoderm
B. Notochord
C. Neural crest
D. Somites
✅ Answer: B. Notochord
Rationale: The notochord secretes Sonic Hedgehog (Shh) and
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other factors that induce overlying ectoderm to become neural
plate.
Q4. Scenario: A newborn has a sacral midline tuft of hair and
a dimple. What is the most likely diagnosis?
A. Meningocele
B. Occult spinal dysraphism
C. Myelomeningocele
D. Caudal regression
✅ Answer: B. Occult spinal dysraphism
Rationale: Cutaneous stigmata (hair, dimple) suggest a closed
neural tube defect without exposed neural tissue.
Q5. Neural crest cells directly give rise to all EXCEPT:
A. Dorsal root ganglia
B. Melanocytes
C. Oligodendrocytes
D. Adrenal medulla
✅ Answer: C. Oligodendrocytes
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Rationale: Oligodendrocytes derive from neural tube (ventral
ventricular zone), not neural crest.
Q6. What is the consequence of failed posterior neuropore
closure?
A. Anencephaly
B. Spina bifida cystica
C. Holoprosencephaly
D. Lissencephaly
✅ Answer: B. Spina bifida cystica
Rationale: Posterior neuropore closure failure leads to spinal
neural tube defects like myelomeningocele.
Q7. At what gestational age does the neural tube completely
close?
A. Week 3
B. Week 4
C. Week 6
D. Week 8
Exam (elaborations) NEURO DEVELOPMENT
EXAM REVIEW WITH CORRECT AND WELL
ILLUSTRATED ANSWERS
Q1. What does the neural plate give rise to during the third
week of gestation?
A. Neural crest cells only
B. Neural tube and neural crest
C. Notochord
D. Somites
✅ Answer: B. Neural tube and neural crest
Rationale: The neural plate invaginates to form the neural
groove, then fuses to create the neural tube (CNS) and neural
crest (PNS).
,Page 2 of 152
Q2. By which gestational day does the anterior neuropore
close?
A. Day 18
B. Day 24
C. Day 28
D. Day 32
✅ Answer: C. Day 28
Rationale: Anterior neuropore closes around day 24–26
(commonly day 28 in some texts). Failure causes anencephaly.
Q3. Which structure induces neural plate formation?
A. Surface ectoderm
B. Notochord
C. Neural crest
D. Somites
✅ Answer: B. Notochord
Rationale: The notochord secretes Sonic Hedgehog (Shh) and
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other factors that induce overlying ectoderm to become neural
plate.
Q4. Scenario: A newborn has a sacral midline tuft of hair and
a dimple. What is the most likely diagnosis?
A. Meningocele
B. Occult spinal dysraphism
C. Myelomeningocele
D. Caudal regression
✅ Answer: B. Occult spinal dysraphism
Rationale: Cutaneous stigmata (hair, dimple) suggest a closed
neural tube defect without exposed neural tissue.
Q5. Neural crest cells directly give rise to all EXCEPT:
A. Dorsal root ganglia
B. Melanocytes
C. Oligodendrocytes
D. Adrenal medulla
✅ Answer: C. Oligodendrocytes
, Page 4 of 152
Rationale: Oligodendrocytes derive from neural tube (ventral
ventricular zone), not neural crest.
Q6. What is the consequence of failed posterior neuropore
closure?
A. Anencephaly
B. Spina bifida cystica
C. Holoprosencephaly
D. Lissencephaly
✅ Answer: B. Spina bifida cystica
Rationale: Posterior neuropore closure failure leads to spinal
neural tube defects like myelomeningocele.
Q7. At what gestational age does the neural tube completely
close?
A. Week 3
B. Week 4
C. Week 6
D. Week 8
