Case 1 - Neural Tube Defects Flashcards
how many neurones are in the brain
100 billion
how many transmitters are in the brain
40 known transmitters
how many transmitters does each neurone produce
a minimum of 2
how many genes are associated with autism
2,500
what is lishencephaly
the failure of cells to stop migrating and end up with a smooth brain
epidemiology of hydrocephalus
1:500
how does the neural tube close?
there is a medial hinge point at the bottom and a dorsal lateral hinge point at the top.
what is folate required for
for cell division so therefore a folate deficiency causes failure of the closure of the neural tube
is anencephaly compatible with life
no.
what is encephalocele
a bone defect and protrusion of the meninges out of the bone defect and is filled with CSF
why is there a tuft of hair on SB occults
shows the CSF is leaking and is stimulating the hair follicles to grow as CSF has growth factors.
why is it bad if the SB baby is exposed to amniotic fluid
because it includes toxic urine which impaired baby’s CNS growth
how much CSF do we produce
every day we make 0.3mls a minute of CSF
why do people with hydrocephaly have sunset eyes
there is pressure on the ocular motor nerve and eyes fall down as there is no muscle tone
international recommendations for Folic acid
400 micrograms per day - 3 months before and 3 months into pregnancy
what else is folate required for
DNA production and methylation
what is the new preventative for SB
combination of folic acid and inositol can help with folate resistant SB
why do babies develop hydrocephalus after birth
in a large number of cases of SB being closed after brith, these babies develop hydrocephalus as the CSF exit is now closed and the normal routes have not opened.
how does hydrocephalus relate to Arnold Chiara
H accompanies nearly 50% of ACM cases due to the Arnold Chiara malformation blocking CSF exit from the ventricles
folic acid epidemiology
prevents up to 70% o NTDs
how much CSF does the chord plexus form
75% of the fluid
how much CSF does the third ventricle add
10%
how much CSF does the fourth ventricle add
5-10%
is CSF being secreted into the ventricles a passive process?
no, the CSF is secreted against pressure into the ventricles
how does CSF move
by producing more behind it
describe the initial development of the cortex
the initial development is in two layers - the marginal zone which are CR cells and the sub-plate cells which are the first two layers made
how many layers of cortex are made between the first two layers
6 layers
what do stem cells have
radial fibres that connect top to bottom
what do these radial fibres do
climb up the layers and are then released to make a new layer at the top of the cortex.
what do the CR cells in the marginal zone express and secrete
reelin
what happens to the CSF if there is no pressure
CSF cannot exit the 4th ventricle into the subarachnoid space
what happens without the CSF at the top of the brain
the signalling pathways are still there but without the CSF at the top of the brain, the cells do not get the message to migrate
when does hydrocephalus occur
once high volume CSF output starts
how is hydrocephalus termed in terms of development
it is an arrest of development
how many proteins does CSF contain
2,500 proteins
