T1 L3: Organisation of the CNS Flashcards
Which embryological layer does the CNS originate from?
The ectoderm
What is the notochord?
A structure within the mesoderm that signals the ectoderm to differentiate
How does the neural tube form?
When the lateral neural plate cells fold inwards
What does the Mantle layer of the neural crest become?
The brain parenchyma (grey and white matter)
What does the Ependymal layer of the neural crest become?
It lines the ventricles
What does the Lumen of the neural crest become?
The ventricles and the central canal
What happens at day 20 of embryonic development within the nervous system?
The neuroectoderm cells receive inductive signals from the notochord and cells thicken to form the neural plate. The lateral plate margins then fold inwards to form the neural tube
What happens at day 24 of embryonic development of the nervous system?
The neural crest cells migrate into the periphery and differentiate and the neural tube cells thicken
What is Anencephaly?
When the brain herniates out of the skull because the anterior neuropore failed to close so there is degradation of the forebrain and skull. It’s fatal
What is Spina Bifida occulta and what causes it?
A hidden vertebral arch defect caused the by posterior neural tube failing to close leading to an open vertebral canal
What is Spina Bifida cystica and what causes it?
When the meninges projects out of the spine because the posterior neural tube failed to close so the vertebral canal remains open. 25% survive
What are the 3 primary brain vesicles and what do they form?
The prosencephalon (forebrain), Mesencephalon (Midbrain), and the Rhombencephalon (Hindbrain)
Where is the cervical flexure when the primary brain vesicles are forming?
Behind the Rhombencephalon
Where is the Cephalic flexure when the primary brain vesicles are developing?
Where the mesencephalon is
What are the 4 secondary brain vesicles?
The telencephalon, Diencephalon, Metencephalon, Myelencephalon, and the optic vesicles
