[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
nuclei of medial nuclear group supply
muscles of neck & back
muscles attached to axial skeleton are supplied by
antro-medial & postro-medial nucleus
lateral nuclear group is divided into
anterior nucleus
antro-lateral nucleus
postro-lateral nucleus
retropostro-lateral nucleus
central nucleus
lateral nuclear group subdivisions in thoracic segments
NONE
groups form one nucleus only
lateral nucleus is found in
cervical
lumbar
most medial muscles are supplied by
most medial nuclei
most distal muscles are supplied by
most lateral nuclei
hands are supplied by
retropostrolateral column of CERVICAL segments
feet are supplied by
retropostrolateral column of LUMBAR segments
flexor muscles are supplied by
dorsal cell columns
extensor muscles are supplied
ventral cell columns
nuclei of lateral horn
intermedio-lateral nucleus
intermedio-lateral nuclei are found in
T1-L2 or L3
sacral autonomic nuclei
S2-S4
preganglionic parasympathetic fibers
preganglionic parasympathetic fibers arise from
sacral autonomic nuclei
preganglionic sympathetic fibers arise from
intermedio-lateral nucleus
lamina
region w similar properties of neurons such as size, shape, packing, density, cytological features
lamina I corresponds to
posteromarginal nucleus
lamina II corresponds to
substantian gelatinosa
lamina III & IV corresponds to
nucleus proprius
lamina V extends across
neck of posterior horn
lamina V is divided into?
EXCEPTION?
medial & lateral parts
EXCEPT in thoracic segments
lamina V lateral part corresponds to
reticular nucleus
lamina VI extends across
base of posterior horn
lamina VI is divided into
medial & lateral parts
lamina VII corresponds to
Clarke’s nucleus
intermediomedial nucleus
intermediolateral nucleus
lamina VIII recieves termination of
extrapyramidal tracts
lamina receiving termination of extrapyramidal tracts
lamina VIII
lamina VIII extends across
medial part of anterior horn
lamina IX corresponds to
nuclear groups of anterior horn (med & lat motor groups)
lamina X represents
central gray substance surrounding central canal
position of white matter in spinal cord
peripheral
white matter is divided into (3)
posterior white column
anterior white column
lateral white column
posterior white column position
b/w posteromedial septum (midline) & entry of posterior nerve roots
lateral white column position
b/w entry of post nerve roots & emergence of ant roots
anterior white column position
b/w emergence of anterior nerver roots & anteromedial fissure
anterior white column position
b/w emergence of anterior nerves roots & anteromedial fissure (midline)
white matter is formed of (4)
myelinated nerve fibers
neuroglia
blood vessels
grouped into tracts
tract definition
group of nerve fibers w same origin, course, termination & function
tracts of white matter
long tracts
short tracts
long tracts of white matter are divided into
ascending=exteroceptive tracts & proprioceptive tracts
descending=pyramidal & extrapyramidal tracts
short tracts of white matter are divided into (5)
1-comma-shaped tract
2-septomarginal tract
3-lissauer’s tract
4-fasciculus proprius tract
5-exteroceptive ascending tracts
exteroceptive ascending short tract function
carry temp, pain, crude touch to sensory tract
tracts extending beyond spinal cord
long tracts
tracts ending in spinal cord
short tracts
which type of ascending tract is the spinothalamic tract
exteroceptive
which type of ascending tract is the dorsal column tract
proprioceptive
tracts of conscious proprioception
gracile
cuneate
tracts of unconscious proprioception
anterior spinocerebellar
posterior spinocerebellar
spino-olivary
collateral of cuneate tract
sensations reaching cortex
conscious proprioception
sensations stopping at the cerebellum
unconscious proprioception
nuclei responsible for the transmission of visceral afferent impulses
intermedio-medial nucleus