Introductory CNS Embryology Flashcards
Explain the formation of the neural groove
Neural plate will form a groove, which is induced by the notochord. The cells on the plate edge thicken so when they fold it forms a neural groove and neural fold The folds come together and zip up to form a tube
Explain the process of the neural grove forming the neural tube
The neural groove begins to fuse together leaving a rostral neuropore and a caudal neuropore (openings) these will close by 25 days and 27 days respectfully. Thus forming a tube
What occurs if their is failure of the neuropores to close?
Anencephaly - Failure of the rostral neurpore to close.
Spina Bifida - Failure of the caudal neuropore to close
What is the most severe form of spina bifida?
Myeloschisis which is where the neural tube doesn’t even develop into adult neural tissue
What are some risk factors for neural tube defects? (NTD)
Folate deficiency, previous anencephaly, diabetes and epilepsy drugs
What is the developmentary names for the forebrain, midbrain and hindbrain?
Fore - Prosencephalon.
Mid - Mesencephalon.
Hind - RHOMBENCEPHALON.
Describe the later development of the neural tube from its origional swellings
Forebrain - grows two lateral expansions connected to a cental slit.
Midbrain - Grows slower and remains as single central tube.
Hind brain - will develop into brain stem and cerebellum.
What do the lumens of the neural tube form?
Lumen of the forebrain will form two lateral ventricles and the central slit will become the third ventricle.
Lumen of midbrain forms cerebral aqueduct. Hindbrain will form fourth ventricle.
The walls of the lateral ventricles will form?
Cerebral hemispheres
Walls of the 3rd ventricle will form?
Diencephalon.
What is the corpus callosum?
White matter that connects the two cerebral hemispheres.
Describe the development of the fornix and hippocampus?
They curve downwards to from a C shape. This also is when the temporal lobe forms as it grows in the down C shape direction.
What happens to sensory grey matter before and after the IV ventricle forms
Before the fourth ventricle, sensory matter tends to be dorsal whereas after the ventricle forms it tends to be more lateral
Describe the formation of the regions in the spinal cord
Sulcus limitans separates the grey matter in the spinal cord into motor and sensory. These regions become the alar lamina (posteriorly) and basal lamina (anteriorly) They then become the sensory and motor regions respectfully.
What allows for cells to specialise into nerve cells?
The notochord releases Noggin, chordin and follistatin which inhibits BMP allowing for default differentiation of neural ectoderm.
