development Flashcards
how long is the pregasrulation stage
post ovulatory 3 weeks
what are the three layers of ttissue formed by gastrulation
ectoderm
mesoderm
endoderm
what is the organizer for gastrulation
primative streak
what forms the notocord
epiblasts that surround hensen’s node- forms the notocord
what are notable defects of gasrulation
split cord malformations (SCM 1 (bony devision) and SCM 2 (
neuroenteric cyst
epidermoid cyst
dysraphyic malformations
what are the four steps of neurulation
Neuroal Plate formation
Neural plate midline bending
neural plate lateral wall bending
neuroal fold fusion
what may drive early brain enlargment
closure of the cranial neural tune which elarges the ventrular system and may drive brain growth
when do the neuropores close
24 days for anterior and 26 days for the caudal
defects of primary neuraltion
anencephaly
craniorachisis
myelomengioceal
myelochisis
what stage do dermoid cysts form
non dysjunction during neural tube closure
timing of secondary neurolation
POD 225 to 27 from the caudally from the posterior neuropore- process called cavitation
defects of secondary neural tube
filum terminale
terminal lipoma
myelocystocele
vater (vertebral anomonies, imperferate anus, trachealesophogeal fistula, and renal anomolies
OEIS- omphalocele, cloacal exstrophy, imperferate anus, and spinal anomolie)
when does lipomylomengiocele occur
likely primary neurolation or possibly premature dysjunction
faulure of caudal neural tumbe to migrate
what is associated with caudal agensiss
secondart neural tube development
lipomas of filum terminale
what causes caudal agensis
improper migrate of cells from primitive streak (gastrulation)
