L17: Spinal Column Flashcards
3 major subdivisions of a typical somite
endoderm
mesoderm
ectoderm
define dermatome
area of skin supplied w/ afferent fibers by a single posterior spinal root
define myotome
all the muscles that are innervated by a single efferent anterior root
most muscles are composed of more than one _____.
myotome
somite cells that migrate anteriorly
becomes muscles of limbs and trunk = hyaxial muscles
and the associated dermis
somite cells that migrate posteriorly
becomes intrinsic muscles of the back = epaxial muscles
and the associated dermis
conus medullaris ends at
L2
cauda equina
horse tail ending of the spinal cord
filum terminale
thin filament of meningeal tissue
number of spinal nerves per portion of vertebral column
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
spinal level of plexuses
cervical C1-4
brachial C5-T1
lumbosacral L1-S4
posterior horns are made of ____ matter and receive incoming _____ fibers.
gray matter
sensory fibers
anterior horns are made of _____ matter and are the site of ?
gray matter
cell bodies of alpha motor neurons to skeletal muscle
lateral horns are made of _____ matter and only exist where? made up of ?
gray matter
thoracic and upper lumbar
cell bodies of autonomic neurons
spinal cord horns are made of
gray matter