Lecture 19: Spinal Cord and Somatic NS Flashcards
2 functional divisions of PNS
-visceral
-somatic
where do spinal nerves pass through
intervertebral foramina
anatomical divisions of nervous system
-PNS
-CNS
somatic NS innervates what structures (general)
-body wall (parietal structures)
somatic NS: function
voluntary motor control over skeletal muscle
what is the spinal nerve complex
somatic nervous system + part of ANS
gray matter contains what part of neuron
-cell bodies
white matter contains what part of neurons
axons
2 main structures within gray matter
-dorsal horn
-ventral horn
do spinal nerve levels and vertebral levels match
no
where does spinal cord end
-before vertebrae
-at conus medularis
where is spinal cord continuous with brain stem
foramen magnum
why is there differential growth between spinal cord and vertebral column
vertebral column grows faster
sensory = (afferent or efferent)
afferent
afferent =
towards CNS
motor = (afferent or efferent)
efferent
efferent =
away from CNS
2 divisions of visceral PNS
-ANS
-sensory
2 divisions of ANS
-sympathetic
-parasympathetic
how many cervical nerves and vertebrae are there
-7 vertebrae
-8 spinal nerves
why are there 8 cervical spinal nerves but only 7 vertebrae
spinal nerves for cervical vertebrae exit cranially to vertebrae from C1-C7
cervical vs thoracic/lumbar/sacral spinal nerves (exit location)
-cervical nerves pass cranially over vertebrae
-thoracic nerves pass caudally over vertebrae
where are somatic motor cell bodies found
ventral horn
where do somatic motor axons leave
ventral root
where are sensory cell bodies found
dorsal root ganglion
where do sensory axons travel
dorsal root
type of neurons found in dorsal root ganglion (hint: sensory)
pseudounipolar
what is the mixed spinal nerve (what kind of information is found here)
-where dorsal and ventral roots are joined/fused
-mixed motor and sensory
dorsal rami go to __________ musculature
epaxial
ventral rami go to __________ musculature
hypaxial
CNS gray matter contains (3)
-cell bodies of neurons (glial cells)
-dendrites
-neuropil
what are CNS gray matter neurons organized into
nuclei
is there connective tissue in CNS gray matter
no
CNS white matter contains (2)
-axons, myelinated
-glial cells
CNS white matter axons are organized into ________
tracts
cauda equina
extension of dorsal and ventral roots to the same numbered vertebral level
each spinal nerve complex is responsible for what
-1 dermatome/body segment
epaxial muscles
-internal muscles of back
-longissimus, iliocostalis, transversospinalis
somatic motor innervation to latissimus dorsi (or any other hypaxial muscle)
ventral horn –> ventral root –> mixed spinal nerve –> ventral ramus
somatic sensory innervation from skin
ventral ramus –> mixed spinal nerve –> dorsal root ganglion (where sensory CELL BODIES are found) –> dorsal root –> dorsal horn
meninges: definition
-coverings of spinal cord
what kind of tissue are meninges made of
connective tissue
3 meninges in spinal cord
-dura mater
-arachnoid mater
-pia mater
what is the outermost/superficial layer of meninges
dura mater
dura mater: features
-tough and thick
-continuous with dura of brain
-surrounded by extradural fat in epidural space
where does dura mater extend to
laterally onto proximal spinal nerves
where/how is dura mater anchored
-to caudal vertebrae via filum terminale
what is the filum terminale
-portion of cauda equina
-fibrous extension of cord down to coccyx
2 parts of filum terminale
-internus
-externus
the internus is made out of which meninge
pia mater
the externus is made out of which meninges
all 3
location of arachnoid mater
deep and adherent to dura mater
which meninge is filled with CSF
arachnoid
the arachnoid mater encloses what space
subarachnoid space
arachnoid mater: features
-thin and delicate
-spiderlike
arachnoid mater is continuous with what structure
subarachnoid space around brain
what is the innermost meningeal layer
pia mater
pia mater location
attached to spinal cord
what does pia mater create (2)
-denticulate ligaments
-filum terminal internus
what are denticulate ligaments
lateral expansions of pia between rootlets to anchor spinal cord to dura mater
