Neural Development Flashcards
Soon after gastrulation, neurulationbegins and results in the formation of a dorsal, ectoderm-derived
Neural Tube
This neural tube is completed by the end of
Week 4
The neural tube forms the neurons* and neuroglia in the
Brain and spinal cord of CNS
Neural tube formation occurs with induction of ectoderm by
Notochord factors
Neural tube formation occurs with induction of ectodermby notochord factors so that developing neuroectoderm cells organize in the midline as a thickening called the
Neural Plate
The neural plate folds to form a depression called the
-Has bilateral neural folds
Neural groove
The neural fold edges fuse in the dorsal midline to form the
Neural tube
With bi-directional fusion of the neural tube, the final step of neurulation is
Neuropore closure
May occur with defective closure of neuropores during week 4 with resulting defective formation of skull, vertebrae, meninges, neural tissues
Neural Tube Defevts (NTDs)
Cleft skull and spine due to defective closure of entire neural tube
Craniorachischisis
Defective formation of cranial vault and exposure of brain to amniotic fluid, which leads to degeneration
Anencephaly
Anencephaly is due to a defective closure of the
Cranial neuropore
A mild defect in the fusion of vertebral arches without herniation of underlying neural tissue
Spina bifida Occulta
A defect in the fusion of vertebral arches WITH herniation of underlying neural tissue
Spina bifida Cystica
Screening for severe NTDs is accomplished by measuring for elevated levels of
Alpha-fetoprotein (amniotic fluid or maternal serum) or Acetylcholinesterase (AChE) (amniotic fluid 15-20 weeks)
Most neural tube defects can be prevented with sufficient amounts of
Folic acid supplementation
Associated with a range of growth deficiencies/structural defects in brain, face, heart and/or intellectual disabilities and/or behavioral issues
Fetal Alcohol Spectrum Disorder (FASD)
Severe end of FASD characterized by low nasal bridge and short nose with smooth philitrum and thin upper lip
Fetal Alcohol Syndrome
Separates the neural tube into dorsal and ventral halves
Sulcus Limitans
Lines the neural tube lumen/neural canal
Neuroepithelium
Neuropeithelial cells proliferate and differentiate into
CNS neuroblasts (primitive neurons)
Once neuroblasts form, they lose their ability to
Divide
The future gray matter of the spinal cord is the
Mantle layer
The future white matter of the spinal cord is the
Marginal layer
Bilateral dorsal thickenings of neuroblasts in the mantle layer make up the
Alar plate
Bilateral ventral thickenings of neuroblasts in the mantle layer make up the
Basal Plate
The alar plate becomes the
Dorsal horn (sensory area)
The basal plate becomes the
Ventral horn (motor area)
Neuropeithelial cells also proliferate and differentiate into
CNS glioblasts
The future brainregion forms at the rostral end of the neural tube, which develops
- ) Bumps called?
- ) Bends called?
- ) Brain vesicles
2. ) Flexures
There are three primary brain vesicles. These are the
Prosencephalon (forebrain), mesencephalon (midbrain), and Rhombencephalon (hindbrain)
There are two flexures among the primary brain vesicles of the neural tube. These are the
Mesencephalic flexure and cervical flexure
There are five secondary brain vesicles. These are the
TELENCEPHALON and DIENCEPHALON (forebrain) MESENCEPHALON (midbrain), and the METENCEPHALON and MYELECEPHALON (hindbrain)
With the formation of the secondary brain vesicles, appears as a dorsal bend between the metencephalon and myencephalon
Pontine flexure
“Sets the table” so that the sensory alar plates are lateral (rather than dorsal) to the motor basal plates along the floor of the 4th ventricle
Pontine flexure
The roof of the 4th ventricle becomes
Thin and Membranous
The MYELENCEPHALON forms the brainstem’s
Medulla oblongata
The MYELENCEPHALON forms the medulla oblongata of the brainstem. What is associated with this region?
CNs IX, X, XI, XII and the 4th ventricle
A derivative of the metencephalon’s rhombic lips
Cerebellum
The mesencephalon forms the
Midbrain
The mesencephalon forms the midbrain. What is associated with this region?
CNs III, IV and Cerebral aqueduct of Sylvius
Forms the optic vesicles (retina, CN II) epiphysis (pineal gland) pituitary(posterior lobe) thalamus andhypothalamus
Diencephalon
The diencephalon surrounds the
3rd ventricle
The infundibulum is a ventral extension of the DIENCEPHALON that forms the
Posterior pituitary
The telencephalon foms the
Cerebral hemispheres
The cerebral hemispheres are connected medially by the
Lamina Terminalis
Thickenings of telencephalon (adjacent to the diencephalon) form
Basal nuclei
The telencephalon is associated with
Cranial Nerve I and lateral ventricles
The outer gray matter of the brain and its 6 layers are formed by waves of neuroblast migrations
Cerebral Cortex
What is the oldest and deepest layer of the cerebral cortex?
Layer VI
Detach from the edges of the developing neural tube and migrate throughout the body to differentiate into a wide variety of cell types
Neural Crest Cells
