L3 Organisation of the Central Nervous System: Spinal cord to the diencephalon Flashcards
What is the central nervous system formed from?
Ectoderm.
How does the neural plate develop from the ectoderm?
Neuroectoderm cells receive signals from the notochord causing cells to thicken to form the neural plate.
How is the neural tube formed?
Lateral neural plate margins (neural crest cells) fold like a zip, this forms the neural groove.
What day of development does the neural tube form?
Embryonic day 20.
What do neural crest cells differentiate into?
Autonomic and sensory neurones and glia
Adrenal gland cells
Melanocytes
Skeletal/CT of the head
What does the mantle layer form?
Brain parenchyma (grey and white matter).
What does the Ependymal layer form?
Lining of the ventricles and cerebrospinal fluid.
What does the lumen form?
Ventricles and the central canal.
What day does the neural tube thicken?
Embryonic day 24.
What is the order of the neural tube layers from outside in?
Ectoderm
Mantle layer
Ependymal layer
Lumen
Where is the notochord located?
Within the mesoderm.
What causes anencephaly?
Failure of the outer neuropore to close leading to degeneration of the forebrain and skill.
Fatal.
What is spina bifida occulta?
Hidden, vertebral arch defect only, less serious.
What is spina bifida cystica?
Meningocele- the meninges project out, higher morbidity and mortality compared to SB occulta.
What causes spina bifida?
Failure of the posterior neuropore to close, causing the spinal cord to be separated by a cleft and an open vertebral canal.
What is the prosencephalon?
Forebrain.
What is the mesencephalon?
Midbrain.
What is the rhombencephalon?
Hindbrain.
What forms the primary brain vesicles?
Expansion of the cranial end (of the neural tube) to form the main brain regions (fore, mid and hindbrain).
What flexure forms in the midbrain?
Cephalic flexure.
What flexure forms in the hindbrain?
Cervical flexure.
What is the telencephalon?
Central hemispheres.
What is the diencephalon?
Thalamus/hypothalamus.
What is the metencephalon?
Pons/cerebellum.
What is the myelencephalon?
Medulla.
What secondary brain vesicles form in the prosencephalon (forebrain)?
Telencephalon (central hemispheres)
Optic vessels (eyes)
Diencephalon (thalamus?hypothalamus)
What secondary brain vesicles form in the rhombencephalon (hindbrain)?
Metencephalon (pons/cerebellum)
Myelencephalon (medulla)
What day do the secondary brain vesicles form?
Embryonic day 36.
What flexure forms alongside the secondary brain vesicles and where is it located?
Pontine flexure.
Between the metencephalon (pons/cerebellum) and the myelencephalon (medulla).
What is located in the brainstem?
Midbrain (mesencephalon)
Hindbrain (rhombencephalon): pons and cerebellum (metencephalon), medulla (myelencephalon).
What does rostral mean?
Front of the brain (opposite direction to caudal).