Nervous System Development II Flashcards
The topographical arrangement of the myelencephalon is almost identical to the spinal cord. What is the major topographical change?
Pronounced expansion of the roof plate to form the thin roof over the fourth ventricle.
Expression of which set of genes seems to be responsible for the differentiation of specific nuclei in the myelencephalon?
Hox genes
What are the superior cerebellar peduncles?
Massive fiber bundles between the cerebellum and mesencephalon
What are the major derivatives of the alar plates of the mesencephalon?
Tectum (corpira quadrigemina):
- Superior colliculi
- Inferior colliculli
Where is Otx-2 located and how is it related to Shh?
It confines Shh to the basal part of the midbrain
Where do the cerebral peduncles form and what is their function?
Formed in the ventrolateral region of the mesencephalon
They carry fibers between the cerebral hemispheres and the spinal cord
What are the major derivatives of the diencephalon?
Epithalamus
Thalamus
Hypothalamus
What are the 3 patterning centers in the forebrain? Explain their interactions and the signal molecules involved.
Rostral patterning center (FGF-8)
Dorsal patterning center (BMPs and Wnts)
Ventral patterning center (Shh)
Define rhinecephalon.
Also called the smell-brain or olfactory brain is a part of the brain involved with smell (i.e. olfaction).
What are the 3 structures that make up the cerebral cortex?
Archicortex
Paleocortex
Neocortex
Define the functions of the neocortex, archicortex, and paleocortex.
It is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, conscious thought, and in humans, language.
Describe the Arnold-Chiari malformation and its relation to hydrocephalus.
Arnold-Chiari malformation is when the cerebellum and the brain stem extend into the foramen magnum and can cause pressure to increase within the brain (hydrocephalus).
Explain why cranial nerve II is not a true nerve.
Cranial nerves I and II are an extension of a brain tract and are myelinated by oligodendrocytes and not Schwann cells, therefore they are part of the CNS and not the PNS
Define rachischisis.
A developmental birth defect involving failure to close the posterior neuropore (lower part of the spine).
Describe the type of closure defects from least serious to most serious.
Rachiscisis
Spina bifida occulta
Meningocele
Myelomeningocele
The cerebellum forms in the region of the rhombic lips (rhombomeres 1-8). The rhombic lips are the product of what inductive interaction?
Roof plate and neural tube via BMP signaling
List the migration of the cells that will form the cortex in the cerebellar primordium.
Granule cells migrate anteriorly along dorsal region of rhombomere 1
Granule cells migrate interiorly through the Purkinje layer
Purkinje cells migrate radially through granule cells
