[HISTO] GREY & WHITE MATTER OF SPINAL CORD Flashcards
Spinal cord enlargements?
why do they exist?
cervical
lumbar
because they innervate the extremeties
spinal nerves
31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
spinal nerves are attached to spinal cord via
dorsal root
ventral root
dorsal root is purely
sensory (afferent)
ventral root is purely
motor (efferent)
nerve cells of dorsal root ganglion
pseudounipolar
what are the two processes of dorsal root ganglion cells
peripheral= dendrites=connected to receptors
central=axons
root fibers bifurcate into
long ascending fibers
short descending fibers
topography of spinal cord
2 symmetrical halves
separated by anterior medialn fissure
separated posteriorly by posterior median septum
two halves of spinal cord are connected by
gray & white commisures
fissures of spinal segments (5)
anterior median fissure
posterior median septum
anterior lateral sulcus
posterior lateral sulcus
posterior intermediate sulci
transverse section of spinal cord shows
H-shaped grey matter surrounded by white matter
grey matter consists of
two dorsal horns
two ventral horns
two lateral horns (thoracolumbar)
central canal
which type of cells line the central canal?
ependymal cells
lateral horns are present in
all thoracic segments
upper two/three lumbar segments
oval large spinal segment
cervical
rounded spinal segments
thoracic
lumbar
sacral
large spinal segments
cervical
lumbar
spinal segments w thin posterior horns
cervical
thoracic
spinal segments w thick posterior horns
lumbar
sacral
spinal segment w thin anterior horn
thoracic
spinal segments w thick anterior horn
cervical
lumbar
sacral
white matter is greater only in which spinal segment
cervical
grey mater spinal cord is formed of
multipolar cells
nerve cells + processes
neuroglia
blood capillaries
unmyelinated nerve fibers
cells of posterior horn & intermediate gray
golgi type i= long axons=form long ascending tracts
golgi type ii=short axons=terminate in gray matter near where they originate
nerve cells in grey matter are arranged in
nuclei
sensory nuclei
1-posteromarginal nuclei
2-substantial gelatinosa
3-nucleus proprius
4-reticular nucleus
5-dorsal nucleus of Clark
6-intermedio-medial nucleus
7-post & ant grey commisural nuclei
Clarke’s nucleus is found in
C8-L3
motor nuclei are
somatic efferents
axons innvervate skeletal muscle
motor nuclei types
large alpha neurons
small gamma neurons
large alpha neurons innervate
extrafusal skeletal muscle fibers
small gamma neurons innervate
contractile part of intrafusal fibers
two groups of motor nucleui of anterior horn
medial nuclear group
lateral nuclear group
medial nuclear group is divided into
antro-medial nucleus= all levels
postro-medial nucleus= cervical + lumbar