Nervous system development Flashcards
Why does the neural fold fuse except for the cranial and caudal ends?
They are left open to communicate with the amniotic cavity
When does anterior/cranial neuropore close?
day 25
when does posterior/caudal neuropore close?
day 28
What are the three primordial dilations (primary brain vesicles) of the cranial end of the neural plate?
Prosencephalon, mesencephalon, rhombencephalon
What is the neuroepithelial layer
thick pseudostratified layer of neuroepithelial cells
what processes occur in neuroepithelial layer?
neurogenesis and gliogenesis occur simultaneously here. Neurogenesis is more prominent in embryo, gliogenesis is more prominent later
What are ependyma cells and where are they?
they ar remaining cells of innner layer which line central canal of s cord and ventricles
Intermediate layer/mantle zone
formed by neuroblasts, becomes GRAY zone of spinal cord
Outer layer/marginal zone
Formed by neuronal processes that give rise to WHITE matter of spinal cord
what are the columns of the mantle layer of the spinal cord?
Ventral and Dorsal thickeing, sulcus limitans, rood and floor plates
Ventral thickening
basal plates= ventral motor horn cells
Dorsal thickening
=alar plates=sensory area of spinal cord
sulcus limitans
groove on each side of spinal cord, separates alar from basal
roof and floor plates
no neuroblasts, pathwars for nerve fibers crossing from one side to the other
alar plates
dorsay (gray) horns, differentiate into sensory afferent interneurons
basal plate
ventral (gray) horns, differentiate into voluntary motor neurons to innervate skel muscle
intermediate zone
lateral horns, differentiate into autonomic or involuntary motor neurons
Neural crest cells migrate dorsolaterally to give rise to
dorsal root ganglion
List the primary vesicles
prosencephalon, mesencephalon, rhombencephalon,
List five vesicles after division
Telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
what does metencephalon give rise to
pons cerebellum walls. Upper part of 4th ventricle
what does myelencephalon give rise to
medulla walls, lower part of 4th ventricle
what forms anterior lobe/ adenohypophysis
Rathke’s pouch, ectoderm invagination oral ectoderm
what are the 3 parts of the adenohypophysis
pars distalis, pars tuberalis, and pars intermedia
what forms posterior lobe or neurohypophysis?
neuroectoderm,
what are the 3 parts of the posterior pituitary
median eminence, infundibular stem, pars nervosa
