Brain Development: Learning this is Killing My BRRAAAAAINNN!!! Flashcards
Forebrain = Prosencephalon becomes
Telencephalon and Diencephalon
Adult Derivatives: Telencephalon
Wall?
Cavity?
Walls: cerebral hemispheres
Cavity: lateral ventricles
Adult Derivatives: Diencephalon
Wall?
Cavity?
Walls: thalamus
Cavity: 3rd ventricle
Midbrain = Mesencephalon becomes…
Mesencephalon
Adult Derivatives: Mesencephalon
Wall?
Cavity?
Walls: midbrain
Cavity: aqueduct
Hindbrain = Rhombencephalon becomes
Metencephalon and Myelencephalon
Adult Derivatives: Metencephalon
Wall?
Cavity?
Walls: pons and cerebellum
Cavity: upper part of the 4th ventricle
Adult Derivatives: Myelencephalon
Wall?
Cavity?
Walls: medulla
Cavity: lower part of the 4th ventricle
Adult Derivatives: Myelencephalon
Wall?
Cavity?
Walls: medulla
Cavity: lower part of the 4th ventricle
Adult Derivatives: Neuroectoderm
CNS neurons ependymal cells (makes CSF; inner lining of the ventricles
Adult Derivatives: Neural Crest
PNS neurons, Schwann cells
Adult Derivatives: Mesoderm
Microglia (like Macrophages, originate from Mesoderm)
Adult Derivatives: Neural Crest
- cranial nerve ganglia
- PNS neurons
- Schwann and satellite cells
- pia and arachnoid mater (leptomeninges)
- craniofacial mesoderm (give rise to muscles and skeletal structures of the head)
- melanocytes
- chromaffin (neuroendocrine) cells of adrenal medulla
Adult Derivatives: Telencephalon
Wall?
Cavity?
Walls: cerebral hemispheres
Cavity: lateral ventricles (makes sense because they are just underneath the cerebral cortex and subcortial white matter)
Adult Derivatives: Diencephalon
Wall?
Cavity?
Walls: thalamus
Cavity: 3rd ventricle between the thalamuses
anything that has “thalamus” in its name:
-hypothalamus, epithalamus, subthalamus
-retina and optic nerve
Cranial flexure appears at the
Mesenchephalon
Cervical flexure appears at the
Myelencephalon
Cervical flexure appears at the
Myelencephalon
Pontine Flexure appears ate the
Metencephalon
Pontine Flexure appears at the
Metencephalon
Meningomyelocele:
the spinal cord and/or spinal nerves (e.g. cauda equina) and meninges protrude through the bony defect
-Treatment consists of surgical sac closure shortly after birth
Meningomyelocele
the spinal cord and/or spinal nerves (e.g. cauda equina) and meninges protrude through the bony defect
-Treatment consists of surgical sac closure shortly after birth
Meningocele
only the meninges protrude through the bony defect
Anencephaly
- failure of the cephalic part of the neural tube (anterior neuropore) to close: absent brain structures above brainstem
- the skull does not close leaving the malformed brain exposed
- condition incompatible with life
Spina Bifida Cystica
- More severe neural tube defect
- neural tissue and/or meninges protrude through a defect in the vertebral arches to form a cyst-like sac.
- Dural sac filled with CSF, meninges and/or nervous tissue (may or may not be covered by skin).
- Most occur in the lumbosacral region
Spina bifida occulta
- Failure of bony spinal canal to close
- No structural herniation.
- Dura is intact
- Associated with tuft of hair or skin dimple at level of bony defect
Tethered cord syndrome
- Any form of Spina Bifida can be associated with this
- due to the spinal lesion itself or scarring from sac surgery;
- the spinal cord gets tethered during growth leading to progressive neurological signs
Arnold-Chiari Malformations
- Cerebellar and posterior cranial fossa abnormalities
- causes herniation of cerebellar tissue and possibly brainstem through the foramen magnum.
- Hydrocephalus from obstruction of the CSF outflow pathway through the foramina of Luschka & Magendie by herniated brain tissue.
Holoprosencephaly
- failure of the left and right hemispheres to separate
- partial or complete failure of prosencephalon to separate into the paired telencephalon vesicles and the diencephalon
Holoprosencephaly
- failure of the left and right hemispheres to separate
- partial or complete failure of prosencephalon to separate into the paired telencephalon vesicles and the diencephalon
-Disorder seen in Sonic Hedgehog (SHH) gene mutations and
Patau Syndrome: Trisomy 13
Dandy Walker Syndrome
- agenesis of
the cerebellar vermis and possibly the corpus callosum
-large posterior cranial fossa
-enlargement of the 4th ventricle
-associated with hydrocephalus and spin bificda
Lissencephaly
- smooth brain: cortex does not develop gyri or sulci
- neuronal migration disorder from genetic defects
- frequently associated with callosal agenesis and heterotopias
