3 - Embryology and Development of Nervous System; Aging Flashcards
3 developmental stages in utero?
- pre-embryonic
- embryonic
- fetal
Pre-embyronic stage timeline?
0-14 days
What stage in utero?
- inner cell mass of sphere of cells becomes embryonic disk with 2 cell layers
pre-embryonic
what 2 cell layers found in pre-embryonic stage?
- ectoderm
- endoderm
mesoderm follows later
embryonic stage timeline?
15 days to 8 weeks
Ectoderm develops into what?
- sensory organs
- epidermis
- nervous system
endoderm develops into what?
- gut
- liver
- pancreas
- respiratory system
Mesoderm develops into what?
- dermis
- muscles
- skeleton
- excretory system
- circulatory system
fetal stage timeline?
end of 8 weeks to birth
when does myelination start?
at fetal stage
neural tube development timeline?
days 18-26
Neural tube development:
1. neural plate forms ___ from ectoderm
longitudinally
Neural tube development:
1. neural plate forms longitudinally from ectoderm
2. edges of plate fold to make ___ ___
neural groove
Neural tube development:
1. neural plate forms longitudinally from ectoderm
2. edges of plate fold to make neural groove
3. folds grow together day ___ forming neural tube
21
Neural tube development:
1. neural tube forms longitudinally from ectoderm
2. edges of plate fold to make neural groove
3. folds grow together day 21 forming neural tube
4. tube closes first in ___ region
cervical
Neural tube development:
1. neural tube forms longitudinally from ectoderm
2. edges of plate fold to make neural groove
3. folds grow together day 21 forming neural tube
4. tube closes first in cervical region
5. quickly fuses together rostrally/caudally with open ends called _____
neuropores
Neural tube development:
1. neural plate forms longitudinally form ectoderm
2. edges of plate fold to make neural groove
3. folds grow together day 21 forming neural tube
4. tube closes first in cervical region
5. quickly fuses together rostrally/caudally with open ends called neuropores
6. neural ___ formed from cells close to tube and ectoderm
7. neural crest moves ___ embryo
8. overlying ectoderm covers the tube/crest
crest, inside
Neural tube development:
1. neural plate forms longitudinally from ectoderm
2. edges of plate fold to make neural groove
3. folds grow together day 21 forming neural tube
4. tube closes first in cervical region
5. quickly fuses together rostrally/caudally with open ends called neuropores
6. neural crest formed from cells close to tube and ectoderm
7. neural crest moves inside embryo
8. overlying ectoderm covers tube/crest
9. superior neuropore closes day ___ and inferior neuropore closes day ___
27, 30
Neural tube development:
- inner and outer cell layers formed by neural tube by day ___
26
inner layer of neural tube cell bodies to become ___ matter
gray
Neural tube separates into dorsal and ventral sections.
Ventral = ___ function
Dorsal = ____ function
ventral = motor
dorsal = sensory
ventral neural tube > motor plate > ventral horn:
- axons of cell bodies of motor plate extend to innervate ___ > motorneurons
myotome