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LBOBI19 LE1 EXAM 2026-2027 ALL 1- 60
QUESTIONS AND CORRECT ANSWERS GRADED
A+
the region of the gray crescent that is broadest will become which surface of the
embryo - CORRECT ANSWER-dorsal
The gray crescent usually lies either to the ___ or ____ side of the blastocoel and
also slightly ____ to it - CORRECT ANSWER-left, right, ventral
The wall if the blastula is thinner on the which side? - CORRECT ANSWER-the
gray crescent side
a process during which surface cells move but fail to involute over the blastoporal
lips - CORRECT ANSWER-exogastrulation
which cells involute over the dorsal blastoporal lip? - CORRECT ANSWER-some
cells of prospective endodeem; all cells of prospective head mesenchyme and
prospective notochord
which cwlls involute over the lateral lips of the blastopore? - CORRECT
ANSWER-some cells of prospective endoderm and lateral plage mesoderm; all
cells of prospective segmental plate mesoderm which cells involute over the
ventral blastoporal lip? - CORRECT ANSWER-remaining cells of prospective
lateral plage mesoderm and some cells of prospective endoderm
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Most prospective endodermal cells remain (stationary or motile?) during
gastrulation stages, forming the ____ and the ____ - CORRECT
ANSWERstationary; yolk plug and floor of the archenteron
what is the fate of prosencephalon? - CORRECT ANSWER-telencephalon and
diencephalon
the skin ectoderm has how many layers? -
CORRECT ANSWER-2; outer is heavily pigmented, inner is less pigmented
region of thickened skin ectodeem on eaxh side ventral to the prosencephalon -
CORRECT ANSWERnasal placodes
fate of the nasal placodes - CORRECT
ANSWERlining of the nasal cavity, young neuronns that produce the axons of the
olfactory cranial nerves and dendrites that function as olfactory receptors
the nasal placodes are derived ONLY from which ectodermal layer? - CORRECT
ANSWER-inner ectodermal layer
the pineal gland originated as a ___ from the prosencephalon - CORRECT
ANSWER-dorsal invagination
derived from a lateral evagination from the prosencephalon - CORRECT
ANSWER-optic cups thickened layer of the optic cup - CORRECT ANSWER-
sensory retina
thin layer of the optic cup - CORRECT ANSWERpigmented retina
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connects the optic cups to the prpsencephalon - CORRECT ANSWER-optic stalk
the inner ectodermal layer asjacent to the sensory retina has thickened to form the
____ - CORRECT ANSWER-lens placode
the source of the posterior pituitary gland or neurohypophysis is the ? - CORRECT
ANSWERinfundibulum
fate of the rhombencephalon - CORRECT
ANSWERmetencephalon and myelencephalon
the rudiment of the anterior pituitary gland is continuous with an ectodermal
invagination called the ____ - CORRECT ANSWER-stomadeum prominent
ectodermal thickenings to either side of the stomodeum - CORRECT ANSWER-
adhesive glands
the accumulation of ectodermal cells posterior to the optic cups - CORRECT
ANSWER-semilunar ganglia of the trigeminal nerve
fate of the auditory vesicles (which originated from tjickenings of which layer?) -
CORRECT
ANSWERinner ear; inner ectodermal layer
t or f: the spinal cord has thick lateral walls and thin roof and floor plates -
CORRECT ANSWER-true
what are the loose cells tjat form the core of dorsal fin? - CORRECT ANSWER-
neural crest cells
LBOBI19 LE1 EXAM 2026-2027 ALL 1- 60
QUESTIONS AND CORRECT ANSWERS GRADED
A+
the region of the gray crescent that is broadest will become which surface of the
embryo - CORRECT ANSWER-dorsal
The gray crescent usually lies either to the ___ or ____ side of the blastocoel and
also slightly ____ to it - CORRECT ANSWER-left, right, ventral
The wall if the blastula is thinner on the which side? - CORRECT ANSWER-the
gray crescent side
a process during which surface cells move but fail to involute over the blastoporal
lips - CORRECT ANSWER-exogastrulation
which cells involute over the dorsal blastoporal lip? - CORRECT ANSWER-some
cells of prospective endodeem; all cells of prospective head mesenchyme and
prospective notochord
which cwlls involute over the lateral lips of the blastopore? - CORRECT
ANSWER-some cells of prospective endoderm and lateral plage mesoderm; all
cells of prospective segmental plate mesoderm which cells involute over the
ventral blastoporal lip? - CORRECT ANSWER-remaining cells of prospective
lateral plage mesoderm and some cells of prospective endoderm
,2 | Page
Most prospective endodermal cells remain (stationary or motile?) during
gastrulation stages, forming the ____ and the ____ - CORRECT
ANSWERstationary; yolk plug and floor of the archenteron
what is the fate of prosencephalon? - CORRECT ANSWER-telencephalon and
diencephalon
the skin ectoderm has how many layers? -
CORRECT ANSWER-2; outer is heavily pigmented, inner is less pigmented
region of thickened skin ectodeem on eaxh side ventral to the prosencephalon -
CORRECT ANSWERnasal placodes
fate of the nasal placodes - CORRECT
ANSWERlining of the nasal cavity, young neuronns that produce the axons of the
olfactory cranial nerves and dendrites that function as olfactory receptors
the nasal placodes are derived ONLY from which ectodermal layer? - CORRECT
ANSWER-inner ectodermal layer
the pineal gland originated as a ___ from the prosencephalon - CORRECT
ANSWER-dorsal invagination
derived from a lateral evagination from the prosencephalon - CORRECT
ANSWER-optic cups thickened layer of the optic cup - CORRECT ANSWER-
sensory retina
thin layer of the optic cup - CORRECT ANSWERpigmented retina
, 3 | Page
connects the optic cups to the prpsencephalon - CORRECT ANSWER-optic stalk
the inner ectodermal layer asjacent to the sensory retina has thickened to form the
____ - CORRECT ANSWER-lens placode
the source of the posterior pituitary gland or neurohypophysis is the ? - CORRECT
ANSWERinfundibulum
fate of the rhombencephalon - CORRECT
ANSWERmetencephalon and myelencephalon
the rudiment of the anterior pituitary gland is continuous with an ectodermal
invagination called the ____ - CORRECT ANSWER-stomadeum prominent
ectodermal thickenings to either side of the stomodeum - CORRECT ANSWER-
adhesive glands
the accumulation of ectodermal cells posterior to the optic cups - CORRECT
ANSWER-semilunar ganglia of the trigeminal nerve
fate of the auditory vesicles (which originated from tjickenings of which layer?) -
CORRECT
ANSWERinner ear; inner ectodermal layer
t or f: the spinal cord has thick lateral walls and thin roof and floor plates -
CORRECT ANSWER-true
what are the loose cells tjat form the core of dorsal fin? - CORRECT ANSWER-
neural crest cells
