development of CNS
Terms
undefined, object
copy deck
- When does the neural ectoderm form the neural plate?
- In the early embryo (~18 days)
- When does the neural tube become internal
- ~4 weeks
- From whence the the ventricular system and central canal of the spinal cord
- The cavity of the neural tube
- What are the four concentric zones of the neural tube
- the ventricular & subventricular, mantle, and marginal zones or layers
- from whence the neurons
- neuroblasts in the ventricular zone of the neural tube
- from whence ependymal cells
- spongioblasts of the ventricular zone of the neural tube
- from whence macroglia
- glioblasts of the ventricular zone of the neural tube
- when is the most rapid phase of neuronal mitotic activity
- from 12-20 wks of gestation, the first critical period of brain development
- From whence the mantle layer
- from migrating primitive neurons generated in the ventricular zones
- The marginal layer becomese
- the white matter of the mature CNS
- Areas where neural tube has not fused by 4 weeks
- anterior neuropore, rhomboid fossa, posterior neuropore
- rhomboid fossa becomes what
- the 4th ventricle of the mature brain
- what are the three vesicles or dilations or the developing brain
- the prosencephalon (forebrain), the mesencephalon (midbrain), and the rhombencephalon (hindbrain)
- Prosencephalon becomes
- telencephalon and diencephalons
- when is the second critical period of brain development?
- third trimester of gestation through about 2 yrs. of age
- first part of commissural system in development
- lamina terminalis
- embryonic Mesencephalon becomes:
- midbrain
- Rhombencephalon becomes:
- metencephalon and myelencephalon
- Rhomboid fossa Ventricular zone becomes:
- cerebellar plate (analogous to the cortical plate)
- mantle layer of the cerebellar plate will differentiate into
- neurons of deep cerebellar nuclei, Purkinje cells, and Golgi cells
- Cells located at the rhombic lip; a small group of specialized somatic sensory neurons (General Somatic Afferents; GSA) which give rise to an external granular layer which develops on the outside of the cerebellar cortex with cells which will differentia
- granule, basket, and stellate cells in the mature cerebellum; granule cells will migrate so that in the adult brain they come to occupy the deepest layer of the cerebellar cortex (the granule cell layer);
- Neurons generated from the rhombic lip are also thought to migrate into the brainstem to become⬦
- the pontine nuclei and the inferior olive
- Medulloblastomas definintion
- malignant embryonal tumors of the cerebellum with a tendency to metastasize; constitute ~20% of pediatric CNS neoplasms with a peak incidence at 3-8 yrs; occur with greater frequency in males
- from whence the choroids plexus
- At two areas of the developing nervous system where the neural tube does not fuse, the pia (the innermost meningeal layer) and ependymal cells interact; Lateral ventricle; the major site of CSF production in the CNS, & 4th ventricle
- define Encephalocele (“pouchâ€)
- failure of fusion above the spinal cord, most commonly the dorsal and occipital area; no bone forms and a pouch of brain tissue extrudes from the skull
- Hydranencephaly:
- the two cerebral hemispheres form, but then a regression of the tissue occurs, and the cavity fills with CSF; can be due to maternal trauma, or to vascular problems in the fetal brain
- Porencephaly
- failure of the normal migration of neurons in the telencephalon to form the normal C-shaped configuration of the hemispheres
- in humans neural plate formation begins when?
- day 18
- deep neural groove has formed by what day
- 20
- neural tube closure begins at what day, begins where in tube
- day 20/21, starts in middle of tube
- cranial neuropore closes what day
- 24
- caudal neuropore closes what day
- 26