drive - embryonic development Flashcards
Following fertilisation what are the first clump of cells called (16 cells or less)
morula
What is the newly fertilised clump of cells called if it is more than 16 cells?
blastocyst
What happens during gastrulation?
The single layer blastula develops into a tri-laminar disc
What is the tri-laminar disc made up of?
Ectoderm, mesoderm and endoderm
What is neuraltion?
The processes of formation of the embryonic nervous system
What happens in neuraltion?
The ectoderm midline thickens to form the neural plate
ectoderm splits at the midline to form the neural groove
Groove deepens
Grove detaches from the overlying ectoderm = forms the neural tube
Where are the presumptive neural crest cells located (originally)?
Lateral to the neural plate (dorso-laterally along the neural groove)
What 8 main cells (/types) do the neural crest cells form?
Sensory ganglia
Cranial nerves 5, 7, 9 + 10
Schwann cells
Pigment cells
Adrenal medulla
Bony skull
Meninges
Dermis
What 3 primary brain vesicles can be identified by the 5th week of embryonic development?
Prosencephalon, mesencephalon and rhombencephalon
What secondary brain vesicles can be identified by the 7th week of embryonic development?
Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon
What has normally happened by the end of the fourth week of embryonic development?
the neural tube has closed
What developmental milestone has occurred by 10 weeks?
cerebral expansion and commissures
What developmental milestone has occurred by 3 months?
Basic brain structures established
What developmental milestone has occurred by 5 months
Myelination has begun
What developmental milestone has occurred by 7 months?
Lobes of the cerebrum have formed
