8.0 Development of the Brain Flashcards
What do we call the layer of pia mater and ependymal cells that gives rise to the choroid plexus?
Tela choroidea
What sort of epithelium makes up the neural tube?
The neural tube, once closed, consists of pseudostratified columnar neuroepithelium.
What division is formed by the mesencephalic flexure?
Diencephalon – Mesencephalon
Describe the formation of the different layers of the brain as a result of their layered cytodifferentiation.
(Series of steps)
Neuroblasts from the ventricular zone form the preplate.
Axons from the preplate form the intermediate zone.
More neuroblasts from the ventricular zone migrate into the preplate, forming the cortical plate, and splitting the preplate into the marginal zone and the subplate. At the same time, the ventricular zone proliferates, forming the subventricular zone.
(Marginal zone -> Cortical plate -> Subplate -> Intermediate Zone -> Subventricular Zone -> Ventricular Zone)
Radial glial cells form and act as a ladder for further differentiation.
Each further layer adds on using the radial glial cells until all the layers are formed.
The thalamus, hypothalamus, and epithalamus arise from what vesicle of the brain?
The diencephalon
What form of spina bifida can result in paralysis or muscle weakness in the lower limbs?
Myeloschisis
What are the three ventricles in early brain development?
Prosencephalon
Mesencephalon
Rhombencephalon
The cerebral peduncles arise from which vesicle of the brain?
The mesencephalon
Which of the three layers of the neural tube do glial cells (other than microglia) differentiate from?
The ventricular zone, after the differentiation of neuroepithelial cells into neuroblasts has finished.
How do the median foramen of Magendie and the lateral foramina of Lushka develop?
The roof of the fourth ventricle in the metencephalon evaginate into the subarachnoid space and rupture, forming the foramina.
When do ependymal cells develop, and where from?
Ependymal cells develop after the neuroblasts and other glial cells differentiate from the neuroepithelial cells of the ventricular zone.
From lateral to medial, what are the nuclei formed from the alar and basal plates in the hindbrain?
Special somatic afferent
General somatic afferent
Special visceral afferent
General visceral afferent
General visceral efferent
Special visceral efferent
General somatic efferent
The cerebellum arises from which vesicle of the brain?
The metencephalon.
The substantia nigra arises from which vesicle of the brain?1
The midbrain
What do we call the dorsal and ventral aspects of the midbrain, respectively?
Dorsal = tectum
Ventral = tegmentum
What is neuronal neterotopia?
What is it associated with?
Cells in aberrant positions compared to a normal brain.
Lissencephaly
The superior and inferior colliculi arise from which vesicle of the brain?
Mesencephalon
What division is formed by the pontine flexure?
Metencephalon – Myelincephalon
The pons arises from which vesicle of the brain?
The metencephalon
What are the four listed causes of microcephaly?
Infection
Maternal alcohol use
Ionizing radiation
Autosomal recessive primary microcephaly
The third ventricle arises from what vesicle of the brain?
Mostly the diencephalon, but also part of the telencephalon.
How is the neural tube formed?
The neural plate and groove develop on the posterior portion of the embryo post-gastrulation, as induced by the notochord. The neural folds proliferate and grow up and around into the neural tube.
What structure in the adult do basal plates become?
The intermediate and ventral horns (grey matter).
What division is formed by the cervical flexure of the brain?
Spinal cord – myelencephalon
What cells form the nucleus gracilis and nucleus cuneatus?
Neuroblasts which have migrated from the alar plate.
What are the four tegmental nuclei?
Red nuclei
Reticular nuclei
CN III nuclei
CN IV nuclei
What other structure do the mamillary bodies develop from, and in what vesicle of the brain?
The mamillary bodies develop off of the hypothalamus in the diencephalon.
What structure develops into the pineal gland, and in what vesicle of the brain?
The pineal gland develops from the epithalamus in the diencephalon.
What are the three zones of the cells of the neural tube, and what cells are found there?
- The ventricular zone is closest to the middle
- This region is the area where cells are proliferating.
- The intermediate (or mantle zone) is between the two layers
- This is the region in which cells are differentiating, this is where they become neuroblasts.
- The marginal zone is the outermost layer
- There are not as many cell bodies here, however there are axons.
What two areas gives rise to the pituitary?
What structures of the pituitary are formed by each?
The roof of the stomodeum forms the “hypophyseal diverticulum,” which forms the following structures in the pituitary:
- Pars Anterior
- Pars Tuberalis
The diencephalon forms the “neurohypophyseal diverticulum” which forms the following structures:
- Median eminence
- Infundibular stem
- Pars nervosa
Define the four types of spina bifida
• SB Occulta: unfused neural arch,
skin remains intact
• SB with meningocele: meninges
extrude
• SB w/meningomyelocele:
meninges & neural tissue extends
• SB w/myeloschisis: open neural
tissue
What is pachygyria?
Broad, thick gyri
What is the term for the disorder of the brain on the left?
Lissencephaly
What is holoprosencephaly?
What cause has been implicated?
The telencephalic vesicles do not separate into right and left, but instead remain singular.
This is associated with facial anomalies, like cyclopia.
Sonic Hedgehog (SHH) gene has been implicated.
The cerebral aqueduct arises from which vesicle of the brain?
The mesencephalon
What structure in the adult do alar plates become?
Dorsal horns (grey matter).
What forms the falx cerebri?
Mesenchyme trapped in the longitudinal fissure after the formation of the choroid plexus.
What are the secondary brain vesicles?
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
