Studied by 4 people
pre-embryonic stage
conception to day 14
embryonic stage
day 15-8th week
nervous system development is necessary
fetal stage
end of 8th week until birth
neurogenesis
development of nervous system from ectoderm
when does fertilization of the ovum occur?
in the pre-embryonic stage in the fallopian tube
pre-embryonic stage: cell division
starts and continue while zygote moves down the tube
movement of zygote down the tube
stage of morula to blastula
morula requirements
< 8 cells for division
blastula requirements
8 cells for division
pre-embryonic stage: blastocyst
solid sphere of cells is formed in the cavity and implants into the endometrium, thus, creating the blastocyst
pre-embryonic stage: embryonic disc
during implantation, the inner cell mass develops into the embryonic disc, and three layers are formed (ectoderm, mesoderm, and endoderm)
pre-embryonic stage: ectoderm
outer layer of the sphere and becomes the fetal contribution of the placenta
embryonic stage developments
organs
embryonic stage ectoderm developments
CNS, PNS, skin, nails, sensory epithelia of eyes, ears, and nose
embryonic stage mesoderm developments
muscles, skeleton, cardiovascular system, kidneys, spleen, gonads, and adrenal glands
embryonic stage endoderm developments
gut, liver, pancreas, thyroid, and respiratory system
fetal stage developments
all organs and systems develops more fully
nervous system develops nad myelination begins
CNS development
18th day: thickened part of ectoderm (neural plate)
20th day: edges fold to create the neural groove
22nd day: edges of neural tube come together and fuse at the center
neural tube location
on 22nd day, the tube is located in the cervical area of the embryo
how does the neural tube grow?
rostral and caudal
rostral and caudal neuropores
persists until the 24th and 26th days
rostral neuropore closure
24th day
caudal neuropore closure
26th day
anencephaly
failure to close rostral neuropore, resulting in deficient development of the rostral brain structures (cerebrum)
myelomeningocele
failure to close caudal neuropore, resulting in spina bifida (incomplete development of caudal nervous system - lumbar and sacral spinal cord)
completion of rostral neural tube
formation of brain and structures
completion of caudal neural tube
forms spinal cord
neural crest
ectoderm cells that remain outside the neural tube
dorsal clumps form sensory ganglia (DRG) while ventral clumps form sympathetic trunk ganglia
neural vesicle formation
formed by the 28th day and expanded in 3 points with vesicles
rostral vesicle
prosencephalon (forebrain)
middle vesicle
mesencephalon (middle brain)
caudal vesicle
rhombencephalon (hindbrain)
cervical flexure
bending between the hindbrain and spinal cord in the area od the cervical cord
cephalic flexure
bending between the mesencephalon and hindbrain
telencephalon
subdivision of the prosencephalon at the 5th week and leads to the formation of cerebral hemisphere and basal ganglia
diencephalon
subdivision of the prosencephalon at the 5th week and develops into the thalamus, hypothalamus, optic nerves, and tracts
Note 
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