FUNDAMENTALS OF NEUROBIOLOGY
EXAM III QUESTIONS AND ANSWERS
gastrulation - Correct Answers -begins as the local invagination of a subset of cells in
the early embryo, and results in the three layers of cells in an embryo
What does gastrulation ultimately result in? - Correct Answers -the formation of three
distinct germ layers in an embryo
ectoderm - Correct Answers -the outer germ layer
mesoderm - Correct Answers -the middle germ layer
endoderm - Correct Answers -the inner germ layer
How does the notochord form? - Correct Answers -by invagination of the mesoderm in
the region of the primitive streak
What is the notochord? - Correct Answers -a distinct cylinder of mesodermal cells that
condenses at the midline as the mesoderm invaginates
Where is the notochord generated? - Correct Answers -at the primitive pit
What does the primitive pit elongate to form? - Correct Answers -the primitive streak
What does the notochord of the embryo define? - Correct Answers -the axis of
symmetry for the entire body
What are the cells which lie immediately above the notochord collectively termed? -
Correct Answers -neuroectoderm
What does neuroectoderm give rise to? - Correct Answers -the entirety of the nervous
system
Which structure disappears once embryonic development is complete? Why? - Correct
Answers -- the notochord
- since it simply determines the position of the nervous system, it is only really required
for early neural differentiation
What are neuroectodermal precursor cells? How do they form? - Correct Answers --
they are differentiated from overlying ectoderm cells
,- they are formed when the notochord sends signals to the overlying ectoderm cells
What do the cells within the neural tube ultimately give rise to? - Correct Answers -the
brain, spinal cord, and most of the peripheral nervous system
What does the process of gastrulation give rise to? - Correct Answers -three distinct
germ layers (endoderm, mesoderm, and ectoderm)
When does gastrulation typically occur in a human embryo? - Correct Answers -during
the second week of development
When does neural tube development typically occur in a human embryo? - Correct
Answers -it forms between the 3rd and 4th week, but it ultimately hollows between the
4th and 8th week
When does neural proliferation typically occur? - Correct Answers -between the second
and fifth month of development
Which neural processes typically occur before/at birth? - Correct Answers -neural
induction, proliferation, and migration
Which neural processes typically occur after birth? For how long does each occur? -
Correct Answers -- synapse formation (typically between the ages of 6 months to 3
years until adulthood)
- synapse pruning (from childhood to adulthood)
- synapse myelination (from childhood until about 30 years)
What occurs during the first week of development? - Correct Answers -the zygote
cleaves to form an 8 cell model, and ultimately a blastula (hollow ball of cells) is formed
What does the ectoderm ultimately give rise to? - Correct Answers -- epithelium
- nervous tissue
What does the mesoderm ultimately give rise to? - Correct Answers -- most muscle
- blood and connective tissue
- notochord (for regulating neural tube development)
What does the endoderm ultimately give rise to? - Correct Answers -- the epithelial
lining and associated glands of the gut
- lung and urogenital tracts
What do neural stem cells ultimately produce? - Correct Answers -- neurons
- astrocytes
- oligodendroglial cells
floorplate - Correct Answers -a specialized strip of epithelial-like cells
,roofplate - Correct Answers -narrow strip of neuroepithelial cells at the dorsal midline of
the neural tube
What happens to the floorplate and roofplate after nervous system development is
complete? Why? - Correct Answers -- they disappear
- the floorplate and the roofplate are only required to provide signals to the developing
neural tube
dorsal - Correct Answers -situated at the back
What do neural crest cells do (in terms of migration)? - Correct Answers -they migrate
away from the neural tube through a matrix of loosely packed mesenchymal cells
What do neural crest cells ultimately give rise to? - Correct Answers -a lot of things:
- neurons and glia of the sensory and visceral motor (autonomic)
- neurosecretory cells of the adrenal gland & the enteric nervous system
- pigment cells, cartilage, and bone (particularly in the face and skull)
What do signaling molecules in the notochord do to the neural plate? - Correct Answers
-they induce the neural plate to migrate upward and to become the neural groove, which
will ultimately close to form the neural tube
Which germ layer is the notochord derived from? - Correct Answers -the mesoderm
Which proteins are released by floorplate cells? By roofplate cells? Why? - Correct
Answers -- SHHs
- BMPs
- SHHs regulate neural tube folding, and BMPs from the outside ectoderm do as well
Where are the floorplate and roofplate located? - Correct Answers -- the floorplate is
located on the ventral side of the neural tube, and the roofplate is located on the dorsal
side of the neural tube
ventral vs. dorsal - Correct Answers -- ventral: front
- dorsal: back
What induces the formation of a roofplate? - Correct Answers -BMPs from overlying
ectoderm (overlying the neural tube and neural crest)
When is neural tube closure generally completed? - Correct Answers -at about day 28
If there are defects in any of the following, what happens?
a.) zygote
b.) during gastrulation
c.) formation of the neural plate
, d.) formation of the neural tube - Correct Answers -- a.) death
- b.) death
- c.) death
- d.) neural tube defects (NTDs)
- the earlier a defect occurs, the more lethal it is
rachischisis - Correct Answers -failure of neural tube folding during development, results
in death (lack of/very deformed head)
anencephaly - Correct Answers -failure of the anterior neurospore closure, results in
death (lack of/very deformed head)
spina bifida - Correct Answers -failure of posterior neurospore closure, results in
learning, motor, and autonomic function problems (requires surgery in severe cases)
anterior vs. posterior - Correct Answers -- anterior means the same as ventral (toward
the front, chest)
- posterior means the same as dorsal (toward the back, spinal cord)
Which section of the neural tube expands? - Correct Answers -the anterior end of the
tube expands to form 3 primary brain vesicles
What does the remainder of the neural tube (the posterior end) ultimately become? -
Correct Answers -the spinal cord
What are the three primary brain vesicles? - Correct Answers -- prosencephalon
(forebrain)
- mesencephalon (midbrain)
- rhombencephalon (hindbrain)
What are the 5 secondary brain vesicles (from most anterior to most posterior)? -
Correct Answers -- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
Which secondary brain vesicles comprise the prosencephalon? - Correct Answers -the
telencephalon and the diancephalon
Which secondary brain vesicles comprise the mesencephalon? - Correct Answers -the
mesencephalon
Which secondary brain vesicles comprise the rhombencephalon? - Correct Answers -
the metencephalon and the myelencephalon
EXAM III QUESTIONS AND ANSWERS
gastrulation - Correct Answers -begins as the local invagination of a subset of cells in
the early embryo, and results in the three layers of cells in an embryo
What does gastrulation ultimately result in? - Correct Answers -the formation of three
distinct germ layers in an embryo
ectoderm - Correct Answers -the outer germ layer
mesoderm - Correct Answers -the middle germ layer
endoderm - Correct Answers -the inner germ layer
How does the notochord form? - Correct Answers -by invagination of the mesoderm in
the region of the primitive streak
What is the notochord? - Correct Answers -a distinct cylinder of mesodermal cells that
condenses at the midline as the mesoderm invaginates
Where is the notochord generated? - Correct Answers -at the primitive pit
What does the primitive pit elongate to form? - Correct Answers -the primitive streak
What does the notochord of the embryo define? - Correct Answers -the axis of
symmetry for the entire body
What are the cells which lie immediately above the notochord collectively termed? -
Correct Answers -neuroectoderm
What does neuroectoderm give rise to? - Correct Answers -the entirety of the nervous
system
Which structure disappears once embryonic development is complete? Why? - Correct
Answers -- the notochord
- since it simply determines the position of the nervous system, it is only really required
for early neural differentiation
What are neuroectodermal precursor cells? How do they form? - Correct Answers --
they are differentiated from overlying ectoderm cells
,- they are formed when the notochord sends signals to the overlying ectoderm cells
What do the cells within the neural tube ultimately give rise to? - Correct Answers -the
brain, spinal cord, and most of the peripheral nervous system
What does the process of gastrulation give rise to? - Correct Answers -three distinct
germ layers (endoderm, mesoderm, and ectoderm)
When does gastrulation typically occur in a human embryo? - Correct Answers -during
the second week of development
When does neural tube development typically occur in a human embryo? - Correct
Answers -it forms between the 3rd and 4th week, but it ultimately hollows between the
4th and 8th week
When does neural proliferation typically occur? - Correct Answers -between the second
and fifth month of development
Which neural processes typically occur before/at birth? - Correct Answers -neural
induction, proliferation, and migration
Which neural processes typically occur after birth? For how long does each occur? -
Correct Answers -- synapse formation (typically between the ages of 6 months to 3
years until adulthood)
- synapse pruning (from childhood to adulthood)
- synapse myelination (from childhood until about 30 years)
What occurs during the first week of development? - Correct Answers -the zygote
cleaves to form an 8 cell model, and ultimately a blastula (hollow ball of cells) is formed
What does the ectoderm ultimately give rise to? - Correct Answers -- epithelium
- nervous tissue
What does the mesoderm ultimately give rise to? - Correct Answers -- most muscle
- blood and connective tissue
- notochord (for regulating neural tube development)
What does the endoderm ultimately give rise to? - Correct Answers -- the epithelial
lining and associated glands of the gut
- lung and urogenital tracts
What do neural stem cells ultimately produce? - Correct Answers -- neurons
- astrocytes
- oligodendroglial cells
floorplate - Correct Answers -a specialized strip of epithelial-like cells
,roofplate - Correct Answers -narrow strip of neuroepithelial cells at the dorsal midline of
the neural tube
What happens to the floorplate and roofplate after nervous system development is
complete? Why? - Correct Answers -- they disappear
- the floorplate and the roofplate are only required to provide signals to the developing
neural tube
dorsal - Correct Answers -situated at the back
What do neural crest cells do (in terms of migration)? - Correct Answers -they migrate
away from the neural tube through a matrix of loosely packed mesenchymal cells
What do neural crest cells ultimately give rise to? - Correct Answers -a lot of things:
- neurons and glia of the sensory and visceral motor (autonomic)
- neurosecretory cells of the adrenal gland & the enteric nervous system
- pigment cells, cartilage, and bone (particularly in the face and skull)
What do signaling molecules in the notochord do to the neural plate? - Correct Answers
-they induce the neural plate to migrate upward and to become the neural groove, which
will ultimately close to form the neural tube
Which germ layer is the notochord derived from? - Correct Answers -the mesoderm
Which proteins are released by floorplate cells? By roofplate cells? Why? - Correct
Answers -- SHHs
- BMPs
- SHHs regulate neural tube folding, and BMPs from the outside ectoderm do as well
Where are the floorplate and roofplate located? - Correct Answers -- the floorplate is
located on the ventral side of the neural tube, and the roofplate is located on the dorsal
side of the neural tube
ventral vs. dorsal - Correct Answers -- ventral: front
- dorsal: back
What induces the formation of a roofplate? - Correct Answers -BMPs from overlying
ectoderm (overlying the neural tube and neural crest)
When is neural tube closure generally completed? - Correct Answers -at about day 28
If there are defects in any of the following, what happens?
a.) zygote
b.) during gastrulation
c.) formation of the neural plate
, d.) formation of the neural tube - Correct Answers -- a.) death
- b.) death
- c.) death
- d.) neural tube defects (NTDs)
- the earlier a defect occurs, the more lethal it is
rachischisis - Correct Answers -failure of neural tube folding during development, results
in death (lack of/very deformed head)
anencephaly - Correct Answers -failure of the anterior neurospore closure, results in
death (lack of/very deformed head)
spina bifida - Correct Answers -failure of posterior neurospore closure, results in
learning, motor, and autonomic function problems (requires surgery in severe cases)
anterior vs. posterior - Correct Answers -- anterior means the same as ventral (toward
the front, chest)
- posterior means the same as dorsal (toward the back, spinal cord)
Which section of the neural tube expands? - Correct Answers -the anterior end of the
tube expands to form 3 primary brain vesicles
What does the remainder of the neural tube (the posterior end) ultimately become? -
Correct Answers -the spinal cord
What are the three primary brain vesicles? - Correct Answers -- prosencephalon
(forebrain)
- mesencephalon (midbrain)
- rhombencephalon (hindbrain)
What are the 5 secondary brain vesicles (from most anterior to most posterior)? -
Correct Answers -- telencephalon
- diencephalon
- mesencephalon
- metencephalon
- myelencephalon
Which secondary brain vesicles comprise the prosencephalon? - Correct Answers -the
telencephalon and the diancephalon
Which secondary brain vesicles comprise the mesencephalon? - Correct Answers -the
mesencephalon
Which secondary brain vesicles comprise the rhombencephalon? - Correct Answers -
the metencephalon and the myelencephalon
