Embryology Flashcards
what forms the CNS?
neural tube
what germ layer forms the nervous system?
ectoderm
when does CNS appear? what forms then?
beginning of 3rd week
neural plate + folds
what fuses to form the neural tube?
neural folds
(leaves ant/pos neuropore_
how many neural closure sites? begin/end?
5 sites
18/27th day
what is Anencephaly?
failure of anterior neuropore closure leading to failure in skull formation and brain tissue degeneration
Incompatible with life
what is encephalocele?
herniation of cerebral tissue through a defect in skull
failure in closure of rostral neural tube
most common occipital
what is spina bifida?
defective closure of caudal neural tube
non-fusion of vertebral arteries
what is spina bifida occulta?
most minor form
failure of embryonic halves of vertebral arches to grow normally and fuse
sometimes dimple or tuft of hair
usually no clinical symptoms
Spina bifida cystica types? (3)
Protrusion of spinal cord and/or meninges
spina bifida with meningocele (protrusion of meninges and CSF)
spina bifida with meningomyocele (nerve roots and/or spinal cord in sac)
myeloschisis (spinal cord open in affected area)
what forms from myelencephalon?
medulla
what forms from metencephalon?
cerebellum, pons
what forms from mesencephalon?
superior and inferior colliculi
what forms from diencephalon?
thalamus
hypothalamus
pituitary gland
pineal gland
what forms from telencephalon?
cerebral hemispheres
hippocampus
basal ganglia
