Lecture Outline #14 PNS Flashcards
the neural tube
ectoderm folds inward to form a hollow tube. Anterior end swells - hollow brain. Posterior portion - spinal cord & central canal. Both are filled with csf
cortex of spinal cord
white matter - myelinated axons
medulla of spinal cord
grey matter - cell bodies (unmyelinated axons)
central canal of spinal cord
filled w/ csf
dura mater
thick, fibrous, outermost layer, endosteum for braincase
epidural space
between bone & dura mater, target for epidural block
subdural space
space between dura mater & arachnoid
arachnoid
thin, intermediate layer, contains large BV’s which are supported by arachnoid trabeculae
subarachnoid space
space between arachnoid & pia mater, contains denticulate ligaments, filled with csf, target for spinal tap
pia mater
vascular, innermost layer, fused to spinal cord, BV’s form a network on surface of cord
meningitis
inflammation of meninges (bacteria, virus, injury)
conus medullaris
tapered termination of cord
filum terminale
fiber extending from conus to coccyx, acts as a tether holding onto the spinal cord to no retraction
posterior median sulcus
shallow longitudinal groove
anterior median fissure
deep longitudinal groove
cauda equina
roots & rootlets, extend off of conus medullaris
dorsal root
contains sensory nerves, afferent information going to CNS, contains dorsal root ganglion.
ventral root
contains motor neurons (somatic & autonomic), CNS to PNS)
dorsal ramus
innervates skin/muscles of back, branches off of spinal nerve, sensory & motor information
ventral ramus
innervates skin/muscles of thorax, abdomen, limbs, motor information going out
rami communicantes
ANS, visceri, both sensory & motor information. takes a ride of ventral rami
cord diameter variations
cervical & lumbar (accommodates a plexus) both have a lot of grey matter
spinal nerve
where dorsal & ventral roots meet at intervertebral foramen
cervical nerves
C1-C8, named for vertebra below