inside of the spinal cord - lecture 5 Flashcards
gray matter
composed of neurons, their processes and neuroglia
gray d/t neuron cell bodies
where is ratio greatest
in the mid to lower cervical and lumbar levels
d/t responsibility for appendicular control of UE and LE
what is the appearance of gray matter
“butterfly wings”
what’re the “butterfly wings” connected by
gray commissure
–> its center is occupied by the central canal
what is gray matter divided into
ventral/anterior
dorsal/posterior
lateral columns/horns
posterior horn
dorsal horn
dorsal gray matter of the spinal cord
contains interneurons
where is info sent from the posterior horn
from receptors whose cell bodies lie in the dorsal root ganglion
skin, bone, joints
anterior horn
ventral horn
contains interneurons and cell bodies of the large motor neurons that supply skeletal muscles (ventral root)
cell bodies in the anterior horn
alpha or lower motor neurons
smaller gamma or fusimotor neurons
spinal accessory nucleus
phrenic nucleus
alpha or lower motor neurons
skeletal muscles
smaller gamma or fusimotor neurons
intrafusal fibers
spinal accessory nucleus
that form accessory nerve
cervical region, neck innervations
phrenic nucleus
motor neurons that innervate diaphragm
lateral horn
intermediolateral
neurons are sympathetic motor neurons serving visceral organs
contain interneurons
where do axons from the lateral horn exit from
via ventral root
where does the lateral horn appear
only appears b/w T1-L2/L3
white matter
made of myelinated/unmyelinated processes of neurons, neuroglia and blood vessels
white d/t myelin
where is the ratio greatest for white matter
at cervical
where is ratio lowest for white matter
at sacral
d/t number of ascending and descending nerve fibers increase in a rostral direction
fxn of white matter
brings info into the CNS and transmits the info to higher levels
transmits info from the higher levels to the spinal cord and to muscles and glands
how are nerves arranged
in bundles known as tracts (fasciculi)
how are the nerves in white matter classified
3 categories
ascending
descending
intersegmental
ascending nerves
sensory info to higher centers
descending nerves
motor info to lower centers
intersegmental
convey info b/w spinal cord segments
white matter is subdivided into
3 major columns
dorsal funiculus
lateral funiculus
ventral funiculus
dorsal funiculus
C1-T6 is further divided into
medial fasciculus gracilis
lateral fasciculus cuneatus
ventral funiculus
home for ventral white commissure
white commissure
region where decussation/crossing of the spinothalamic tract occurs
