Neurulation & Neural Crest Flashcards
When does the formation of inner cell mass occur?
Week 1
When does formation of epiblast and hypoblast occur?
Week 2
When does gastrulation occur?
Week 3
The primitive streak is a transient sturcture that forms in what region?
Caudal Region
The notochord forms from what layer?
What signaling factor does it give off?
mesoderm
Sonic Hedgehog
The notochord is a midline structure that extends from what two structures?
The notochord is a template for what structure?
Primitive node to prechordal plate
Vertebral column
Describe Neuralation
Notochord will release Shh to stimulate the ectoderm to form the neural plate
Neural plate will invaginate and form the neural fold –> neural groove
The neural groove will become the neural tube which gives rise to CNS (brain and spinal cord)
At the edge of neural tube neural crest cells will migrate out and away
What is considered primary and secondary neuralation?
Primary neuralation: Formation of brain and spinal cord
Secondary neuralation: formation of sacral and caudal region
The caudal eminance starts forming at what day and connects to the other rostral region around what day?
Day 20
Day 42
Neural crest derivatives give rise to cells mainly in what region?
Head and TRunk regions
Abnormalities of neural crest cells gives rise to what?
Neurocristopathies
Neural crest cells give off mostly what neurons?
Sensory
What types of tissue/structures arise from neural crest cells?
Spinal Ganglia
Autonomic ganglia
Cranial ganglia of 5, 7, 9, 10
Schwann cells
Melanocytes
Cells of surprarenal medulla (chromaffin)
Bone, cartilage, Dermis of face and ventral neck
Ciliary muscles
Enamel and dentin
What is hirschsprungs disease?
A neurocristopathy that results in aganglionic colon
What does minig and ocele mean of meningocele?
Mininges
Cyst like sac
What happens in myelocele (myeloschisis)?
Caudal neuropore never fuses and spinal cord is exposed to the environment
T/F: Vertebral arches do not fuse in forms of spina bifida and minengocele, etc
True
What germinal layer is meninx primitiva made up of?
What cells is it derived from?
Mesoderm and neural crest cells
Sclerotome
Pachymeninx and Leptomeninges are derived from what layers or cells, and contribute to what future structures?
Pachymeninx is from mesoderm and forms dura mater
Leptomeninges are from neural crest cells and form arachnoid and pia mater
Folding of the embryo occurs in what week?
Week 4
Somite relates to what portion of the mesoderm?
Somatic relates to what part of the mesoderm?
Paraxial
Lateral plate
What does myelo of meningomyelocele mean?
Spinal cord
