the human nervous system Flashcards
neural tube formation
‘neurulation’ The folds meet and coalesce in the middle line and convert the groove into the closed neural tube
neural canal
The ectodermal wall of the tube forms the rudiment of the nervous system. The centre of the tube is the neural canal.
spina bifidia ‘open spine’
neural tube doesn’t close over properly, a hole is made so spinal nerves and spinal cord bulge out
nerves that stick out get damaged
causing motor defects and handicaps
anencephaly ‘open skull’
the absence of a major portion of their brain scalp and skull
don’t survive for very long
folic acid
can prevent NTDs
fluid filled vesicles that occur on the neural tube (primary brain vesicles)
1) prosencephalon
2) mesencephalon
3) rhombencephalon
prosencephalon
forms the forebrain
mesencephalon
forms the mid brain
rhombencephalon
forms the high brain
(secondary brain vesicle) diencephalon
has optic vesicles
the outpocketings
fold in on themselves to produce the brain
rostral end
part of the neural tube that forms the brain
the spinal cord development
retrains it’s tubular shape
grey matter in spinal cord
processes and cell bodies (somas)
white matter in spinal cord
axons
difference between white and grey matter in brain and spinal cord
in the spinal cord the grey matter is the butterfly of somas in the middle with extensions sprouting out as white matter (axons)
in the brain grey matter is on the outside in the cortex (cell bodies)
arranged in the opposite way
the SC encased
in the spinal canal
bony vertebrae
spinal cord nerves
dorsal root- (dorsal root ganglian containing cells bodies of afferent nerves)
DAVE
dorsal- afferent (axons into the spinal cord)
Ventral-Efferent (taking motor nerves out of spinal cord to effectors)
dorsal root
carries sensory input into spinal cord
ventral root
carries motor commands out of the spinal cord
spinal discs
stop the vertebrae from touching each other
L 4 / L5 in spinal cord
there is a fibrous cushion between discs in spine which contains nucleus pulpous, which can herniate causing pain when pressure in put of the lower back
spinal interneurons
connect sensory and motor neurons
by how many days should the neural tube be closed over
26!
The entire nervous system derives from the ectoderm. Part of the ectoderm the neural plate will change from a flat sheet of cells to a groove, known as the neural groove. The walls of the neural groove are known as neural folds and these start to move together before fusing dorsally to form the neural tube. This formation of the neural tube occurs at roughly 26 days.
