Embryo Flashcards
¨Neuroectodermal(neuroepithelial) cells of neural tube give rise to:
Location of neuroblast formation, what type of cells is it made of?
ventricular zone (made of epyndymal cells)
What area forms gray matter, what type of cells?
Intermediate zone, forms from neurioblasts that migrate from ventricular zone that become neurons and glial cells
Divisions of intermediate zone
What forms white matter and what does it contain
Marginal zone, contains nerve fibers (axons) of the neuroblastsof the intermediate layer and glial cells
What form Dorsal Root Ganglia
Neural crest cells
What seperarates alar and basal plates
sulcus limitans
From where does the brain develop
¨neural tube cranialto the 4thpair of somites
3 primary brain vesicles prior to closure of anterior neuropore
What develops between rhombencephalon and spinal cord (4th week)
cervical flexure
What develops between prosencephalon & rhombencephalon
¤Midbrain (mesencephalic, cephalic, cranial) flexure
What allows for the formation of the 4th ventricle
Pontine flexure (rhombencephalon folds in on itself)
Vesicles of prosencephalon of 5th and 6th weeks
Telencephalon and Diencephalon
Vesicles of Rhombencephalon of 5th and 6th weeks
Metencephalon and myelencephelon
When and from what does the cerebellum form
During 5th week, from rhombic lips. Lips fuse by 8th week, lobes and vermis by 12
Three primary sequential events during cerebellar development
- Patterning of MHB junction (isthmic organizer) and cerebellar angle
- Development of 4thventricular roof
- Development of cerebellar hemispheres & vermis
Divisions of roof of 4th ventricle
Primary events of forebrain development
- Prosencephalic formation
- Prosecephaliccleavage
- Prosencephalic midline development
What is formed by horizontal prosencephalon folding
paired optic vesicles, olfactory bulbs & tracts
What is formed by transverse prosencephalon folding
Seperates diencephalon and telencephalon, Diencephalonforms portion of basal ganglia, thalamus, third ventricle, and posterior portion of pituitary gland (anterior from ectoderm)
What is formed by saggital prosencephalon folding
Paired cerebral hemispheres, lateral ventricles, and portions of basal ganglia, only in telencephalon
Thickening steps during Prosencephalic midline development
Commissural (Corpus callosum andSeptum pellucidum)
Chiasmatic (Optic chiasm)
Hypothalamic (Hypothalamus)
What does the corpus collosum develop from
lamina terminalis
What forms the choroid plexus
¨Tufts of capillaries invaginateinto roof plates of the forebrain & hindbrain
Main events from week 9 to the end of gestation
¤Continued formation of sulci & gyri
¤Neuron Production, Migration, & Differentiation
¤Neuronal Apoptosis
When do gyri and sulci form
Last 2 months of gestation
When does neuron production peak
28 weeks
Order of neuronal myelenation
1st: sensory pathways
2nd: motor pathways
3rd: association pathways
