Flashcards in BRAIN DEVELOPMENT Deck (41)
how does the neural tube form?
- in 3rd week ectoderm thickens in the mid-line to form neural plate
- it then undergoes mitosis to form neural groove
- the groove deepens and eventually detaches from the overlying ectoderm to form neural tube
what are neural crest cells found?
they lie lateral to the neural plate
they run dorsolaterally along the neural groove
what do neural crest cells form?
by which week have the prosencephalon, mesencephalon and rhombencephalon formed?
by week 5
what happens in week 5 of brain development?
proencephalon, mesencephalon and rhombencephalon developed
what happens in week 7 of brain development?
secondary brain vesicles have developed
what do the secondary brain vesicles develop into?
they give rise to the mature brain
what secondary vesicles does the prosencephalon give rise to?
what secondary vesicles does the mesencephalon give rise to?
what secondary vesicles does the rhombencephalon give rise to?
what mature brain structures are derived from the prosencephalon?
what mature brain structures are derived from the mesencephalon?
what mature brain structures are derived from the rhombencephalon?
upper 4th ventricle
what brain developmental milestone occurs at 3 weeks?
what brain developmental milestone occurs at 10 weeks?
cerebral expansion and commissures
what brain developmental milestone occurs at 3 months?
what brain developmental milestone occurs at 5 months?
myelination has begun
what brain developmental milestone occurs at 7 months?
lobes and cerebrum have formed
what brain developmental milestone occurs at 9 months?
gyri and sulci have formed
what is the type of CNS abnormality dependent on?
the time of infection
what are the critical periods for developing CNS abdnormalities?
week 6 = eye malformations
week 9 = deafness
week 5-10 = cardiac malformation
when do CNS abnormalities tend to occur?
in the 2nd trimester
when does risk of CNS abnormalities decrease, why?
after 16 weeks
this is because most structures have developed by this point
when should the neural tube be closed by?
by the end of week 4
what is spina bifida?
failure of closure of the neural tube in spinal region
what is anencephalus?
failure of closure of the neural tube in the cephalic region
how can you detect brain activity?
monitor haemodynamic activity
how can you use a lumbar puncture to measure brain activity?
increased neural activity results in increased release of neurotransmitters and their breakdown products
this is measured in CSF from lumbar punctures
how do EEGs detect brain activity?
they give indication of regional brain activity
they are useful for detecting signs of epilepsy
over-excitation of neurons can lead to cell death