Embryo Flashcards
What is the critical pre-natal period for brain development?
12 weeks -18 weeks
What happens if the mother is exposed to teratogens after the prenatal critical period?
since brain development continues after gestation(postnatally), this can cause intellectual,emotional and behavioral disabilities
When are the three germ layers formed?
during gastrulation (16 day)
Ectoderm layer?
(outside layer) generates the skin and the nervous tissue
Mesoderm layer?
(middle layer) generates most of the muscle, blood, connective tissue of the body and placenta
Endoderm layer?
(inside layer) generates epithelial lining and associated glands of the gut,lung and uro-genital tracts
Notochord will develop into …..
spinal cord and nervous tissue
Notochord releases diffusible factors called….
morphogens(which signal molecules that form gradients and trigger gene expression)
What happens when the ectoderm is exposed to BMP-4(coming from endoderm and mesoderm)?
ectoderm develops into the skin
What are BMP-4 antagaonists that the node secretes?
noggin,chordin and follistatin
What do the BMP-4 antagonists do ?
allow ectoderm to develop into nerve tissue and neural plate
What is neurulation?
-folding and closing of the neural plate
-developing of the somite
Where does the folding and closure of the neural tube occurs first?
at the cervical region
When the neural tube zips, it leaves to opening known as …..
anterior and posterios neuropores
At what day does the anterior neuropore closes?
day 25
At what day does the posterior neuropore closes?
day 28
Ancephaly?
-fetus doesn’t have closure of the anterior pore(doesn’t give rise to brain tissue)
-have massive retardation
-some die in vitro or through spontaneous abortion
Spina bifida?
-fetus posterior pore doesn’t close (spinal cord doesn’t form properly)
-mostly in the lumbar region
-CSF is exposed to complications like infections or having nerve roots exposed
Neural tube ventral side …
motor
Neural tube dorsal side…
sensory
BMP from skin induce expression of BMPs in roof plate which largely patterns….
alar plate
SHH from the notochord induces expression of SHH in floor plate which largely patterns…
basal plate
Neural crest cells down regulate….?
cadherin expression and delaminate
neural crest cells transform from epithelial cells into….?
migratory mesenchymal cells that will contribute to forming many tissues in the body
Neural crest derivatives originate from four major segments of the neurotaxis?
- cranial
2.cardiac
3.vagal
4.trunk & sacral
Cranial neural crest gives rise to….
head connective tissue and skeletal structures(majority), nerves and pigment cells
What are the 3 parts of the neural tube?
1.Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhomencephalon (hindbrain)
Prosencephalon divides into?
telencephalon and diecephalon
Rhombencephalon divides into?
metencephalon and myelencephalon
What does telencephalon develop into?
paleocortex, corpus striatum, neocortex, hypothalamus,infundibulum
What does diencephalon develop into?
Epithalamus, and thalamus
What does Mesencephalon develop into?
tectum,tegmentum, cerebral peduncles
What does Metencephalon develop into?
cerebellum and pons
What does myelencephalon develop into?
medulla
