Development/Landmarks Flashcards
neural groove and folds
depression in neural plate (2nd event) edges start to grow dorsally creating folds
neural tube
formed by fusion of neural folds. hollow part of the tube develops into ventricular system (cavities within adult brain filled with CSF)
Neural crest derivatives
- dorsal root ganglia = spinal ganglia (collection of cell bodies outside the CNS)
- sensory ganglia of certain nerves
- autonomic ganglia - inside walls of viscera (collection of cell bodies)
- adrenal medulla
Prosencephalon
primary vesicle stage, rostral end of tube
front of brain = forebrain
Mesencephalon
primary vesicle - midbrain
rhombencephlon
primary vesicle - hindbrain, caudal end of tube
telencephalon and Diencephlon
secondary vesicles that originate from the prosencephalon and make up the forebrain
mesencephalon (2)
secondary vesicle originating from mesencephalon with very little differentiation, keeps cylindrical shape
metencephalon and myelencephalon
secondary vesicles that originate from the rhombencephalon and make up the hindbrain, most caudal portion of the brainstem
lateral ventricles
within telecephalon, C-shaped, left and right lateral ventricles are connected by a T-shaped intersection called the interventricular foramen (left = I, right = II)
Third ventricle
in diencephalon found at the midline, a large circle
Mesencephalic aqueduct
midline structure within mesencephalon
fourth ventricle/rhomboid fossa
under the cerebellum that lies over the met/myelencephalon
contains:
Lateral apertures - foramen of luschka
Median aperture - foramen of Magendie - ONLY in primates, empties into cisterna magna (space between lining of CNS) to provide cushioning effect
(CSF goes thru into subarachnoid space)
rostral neuropore
anencephaly (without brain) - front opening of neural tube fails to close leading to error in brain development
caudal neuropore
spina bifida (without spinal cord) - back opening of neural tube fails to close
brain flexures
- midbrain - cranial ventral surface, most rostral
- pontine - dorsal surface
- cervical - caudal ventral surface, most caudal, does not flex much in most animals (180 degrees)
- primates/upright animals - 90 degree angle
division of the nervous system
- CNS - brain and spinal cord
- PNS (outside CN) - ganglia and cell processes = nerve fibers
- ANS - features of both CNS and PNS
histologic development of the spinal cord
- marginal layer - becomes white matter, lateral most white matter of cord = cell processes/axons (myelinated)
- Mantle layer - becomes gray matter = cell bodies
- germinal layer - ependymal cells, medial most, lining of ventricular system and central canal of spinal cord
sulcus limitans
“Limiting groove”
outpouching in middle of neural tube, divides neural tube b/w alar and basal, sensory and motor
Alar plate - sensory, dorsal
basal plate - motor, ventral
central nervous system components: Brain
Gray matter: cortical - surface of brain cerebrum, 6 layers
Subcortical - under the surface, pockets of cell bodies
white matter: under the cortical gray, tracts and pathways
(depending on location cell bodies have different function)
central nervous system components: spinal cord
gray matter: under the surface, columns and horns
white matter: surface bundles, form tracts (fasciculus=small bundle, funiculus=large bundle)
neural plate
thickening of tissue from ectoderm layer
peripheral nervous system
cell bodies = ganglia
cell processes = nerve fibers
PNS gray and white matter
Gray matter = cell bodies:
dorsal root ganglia, autonomic ganglia (walls of viscera, around abdominal aortic blood vessels), ganglia of sensory cranial nerves
White matter = cell processes:
nerve fiber bundles ex: radial nerve