Organogenesis
Neurulation evolution of the ectoderm
crucialprocess duringthe embryonic development wherethe neural plate aflat sheetofcells foldsandform
the neural tube whicheventually becomes thebrainandthespinalcord
involves complex cellular movements and signaling thatestablishthecentralnervoussystem's
basic structure
occurs in the 3ʳᵈ week
Formation
of the neuralplate fromtheectodermabove thenotochord
Theneuralplateis invaginated along itscentral axis neural groove neuralfolds
Neuralplate Neural tube
Neural folds Neural crest
Notochord indules differentiation
of ectodermal
cells above it toform neuralplate
Neuralplate thickening ectodermalongthemidline
of
Neural groove depressionforms in the centerofneuralplate
1 Neural folds
consistsof cells forming lateralwalls around neural groove whichelevate slightyaboverestofectoderm
The uppermost cells in the neural folds differentiateintoneuralcrest form a numberofdifferent
peripheral nervous structures
2 Neural tube
Theneural foldscircleupwardandmeet in the midline forming a tube
Thistube ispulled bellow the outer layerofectoderm neural tube
Neuralcrestcells separate and are locatedbetween neuraltubeandectoderm
Cranialportion enlarges to becomethebrain
Caudalportion remains tubular becomes thespinalcord
Developmentrequiresfolate folate deficiency neuraltube defects
steps theses on day 2
2 neuropures EL c 27
The neural tube separates from theectoderm surface
Theectoderm becomes a continuous layeragain
, middle and caudal spinalcord
proximal s prosencephalon mesencephalon rhombencephalon
prosencephalon telencephalon cerebralcortex and diencephalon
mesencephalon mesencefalon pons cerebellum
Rhombencephalon metencephalon pons and cerebellum and myelencephalon spinal.no medullaoblong
The neuraltube develops 3 bulges primary brainvesicles at the cranialend
Presencephalon forebrain splitsgiven rise to
Telencephalon becomesthecerebralindex neuralcanal lateralventricles 3ʳᵈ
ventricl
Diencephalon becomes Thalamus hypothalamus andpinealgland
Mesencephalon midbrain contains the cerebralaqueduct
Rhombencephalon hindbrain splitstobecome
Metencephalon becomes pons andcerebellum
Myelencephalon becomes medulla oblongata
Remnant neuralcanalpresentaround metencephalon and myelencephalon
of
whichbecomesthe 4ᵗʰ ventricle
Ectoderm
divided into 3 majordomains
surface ectoderm primarily epidermis
neuraltube brainandspinalcord
neuralcrest peripheralneuronspigmentfacialcartilage
Surface ectoderm derivates
Epidermis skin hair andnails
Adeno
hypophysis Externalandinternalear
Tooth enamel crystalline parotid
Neuroectoderm derivates
CNS UNS Neuro
hypophysis Retinaandopticnerve
Astrocytes Oligodendrocytes
Derivates of neural crests on the dorsolateral facesofneuraltube
spinalganglia VNS ganglia Schwann cells leptomeninges
Dermal pigmentcells Melanocytes Adrenal medulla pharyngealarches
odontoblasts
Congenital malformation
Anencephaly
closure lackof oftheanteriorneuropore braindoesn'tdevelop
incompatibility with life
Spina bifida lack ofclosureof the posterior neuropore lightestform
occult spinabifida vertebrae don'tformaround thespinalcord
most severe form spinabifidawith myeloschisis spinalcordcan beseenexternally
leg
Neurulation evolution of the ectoderm
crucialprocess duringthe embryonic development wherethe neural plate aflat sheetofcells foldsandform
the neural tube whicheventually becomes thebrainandthespinalcord
involves complex cellular movements and signaling thatestablishthecentralnervoussystem's
basic structure
occurs in the 3ʳᵈ week
Formation
of the neuralplate fromtheectodermabove thenotochord
Theneuralplateis invaginated along itscentral axis neural groove neuralfolds
Neuralplate Neural tube
Neural folds Neural crest
Notochord indules differentiation
of ectodermal
cells above it toform neuralplate
Neuralplate thickening ectodermalongthemidline
of
Neural groove depressionforms in the centerofneuralplate
1 Neural folds
consistsof cells forming lateralwalls around neural groove whichelevate slightyaboverestofectoderm
The uppermost cells in the neural folds differentiateintoneuralcrest form a numberofdifferent
peripheral nervous structures
2 Neural tube
Theneural foldscircleupwardandmeet in the midline forming a tube
Thistube ispulled bellow the outer layerofectoderm neural tube
Neuralcrestcells separate and are locatedbetween neuraltubeandectoderm
Cranialportion enlarges to becomethebrain
Caudalportion remains tubular becomes thespinalcord
Developmentrequiresfolate folate deficiency neuraltube defects
steps theses on day 2
2 neuropures EL c 27
The neural tube separates from theectoderm surface
Theectoderm becomes a continuous layeragain
, middle and caudal spinalcord
proximal s prosencephalon mesencephalon rhombencephalon
prosencephalon telencephalon cerebralcortex and diencephalon
mesencephalon mesencefalon pons cerebellum
Rhombencephalon metencephalon pons and cerebellum and myelencephalon spinal.no medullaoblong
The neuraltube develops 3 bulges primary brainvesicles at the cranialend
Presencephalon forebrain splitsgiven rise to
Telencephalon becomesthecerebralindex neuralcanal lateralventricles 3ʳᵈ
ventricl
Diencephalon becomes Thalamus hypothalamus andpinealgland
Mesencephalon midbrain contains the cerebralaqueduct
Rhombencephalon hindbrain splitstobecome
Metencephalon becomes pons andcerebellum
Myelencephalon becomes medulla oblongata
Remnant neuralcanalpresentaround metencephalon and myelencephalon
of
whichbecomesthe 4ᵗʰ ventricle
Ectoderm
divided into 3 majordomains
surface ectoderm primarily epidermis
neuraltube brainandspinalcord
neuralcrest peripheralneuronspigmentfacialcartilage
Surface ectoderm derivates
Epidermis skin hair andnails
Adeno
hypophysis Externalandinternalear
Tooth enamel crystalline parotid
Neuroectoderm derivates
CNS UNS Neuro
hypophysis Retinaandopticnerve
Astrocytes Oligodendrocytes
Derivates of neural crests on the dorsolateral facesofneuraltube
spinalganglia VNS ganglia Schwann cells leptomeninges
Dermal pigmentcells Melanocytes Adrenal medulla pharyngealarches
odontoblasts
Congenital malformation
Anencephaly
closure lackof oftheanteriorneuropore braindoesn'tdevelop
incompatibility with life
Spina bifida lack ofclosureof the posterior neuropore lightestform
occult spinabifida vertebrae don'tformaround thespinalcord
most severe form spinabifidawith myeloschisis spinalcordcan beseenexternally
leg
