spinal cord Flashcards
what does the spinal cord run through
the vertebral canal
spinal cord functions
- sensory and motor innervation via the spinal nerves
- major center for reflexes
adult spinal cord
- extends to the conus medullaris
- spinal cord segments are superior to where their corresponding spinal nerves emerge through the intervertebral foramina
denticulate ligaments
lateral shelves of pia mater anchoring to dura
conus medullaris tapers into the ________ ________ tethered to the _________
cauda equina; coccyx
to which part of the spinal cord are the lateral horns unique
thoracic
how many pairs of spinal nerves are there
31
where do the spinal nerves attach
attach through dorsal and ventral nerve roots
where do the spinal nerves pass through
intervertebral foramina
how many spinal nerve pairs are there in the cervical spine
8 cervical
how many spinal nerve pairs are there in the thoracic spine
12 thoracic
how many spinal nerve pairs are there in the lumbar spine
5 lumbar
how many spinal nerve pairs are there in the sacral spine
5 sacral
how many spinal nerve pairs are there in the coccygeal spine
1 coccygeal
cauda equina
collection of nerve roots at inferior end of vertebral canal
cervical spinal nerves exit from ______ the respective vertebra
above
3 meningeal membranes of the spinal cord
- dura mater
- arachnoid mater
- pia mater
3 potential spaces of the spinal cord
- epidural space
- subdural space
- subarachnoid space
spinal cord protection
- bone
- CSF
what makes the spine flexible
lots of white matter = myelination = high fat levels = flexibility
spinal tap (lumbar puncture)
- needle introduced into subarachnoid space to collect CSF
- determine infectious and inflammatory disease
- control and detect CSF pressure
- anesthetic delivery
lumbar spine needs to be _________ so needle can pass between spinal processes
flexed
spinal reflex example
take hand back from hot pan, etc.
visceral motor of the gray matter
visceral motor = autonomic = involuntary = organs
somatic motor of the gray matter
somatic motor = somatic = voluntary = skeletal muscle + skin
cervical?
thoracic?
lumbar?
sacral?
ascending fibers (white matter in spinal cord)
sensory info from sensory neurons/receptors to brain
descending fibers (white matter in spinal cord)
motor instructions from brain to spinal cord
descending fibers function
- stimulate contraction of muscles
- stimulate secretion from glands
commissural fibers (white matter)
white matter fibers crossing from one side of spinal cord to the other
how many pathways decussate at some point
many
most pathways synapse ? times from brain to spinal cord
2 or 3
ascending pathways (white matter)
sensory information by 3 orders of neurons from body up to more rostral regions of CNS
3 orders of neurons in ascending pathways (white matter)
- dorsal column
- spinothalamic tracts
- spinocerebellar tracts
descending pathways (white matter)
- motor instructions via upper and lower order neurons from the brain to more caudal regions of the CNS
types of descending pathways (white matter)
- pyramidal
- extrapyramidal
result of damage to descending tracts
paralysis
result of damage to ascending tracts
paresthesias
paresthesias
burning/prickly sensations
major ascending pathways for the somatic senses
- spinocerebellar
- dorsal columns (medial lemniscus)
- spinothalamic
spinocerebellar pathways
- ipsilateral
- proprioception from skeletal muscles to cerebellum
dorsal columns (medial lemniscus) pathways
- contralateral
- medulla decussation
- discriminative touch sensation
- through thalamus to somatosensory cortex
spinothalamic pathways
- contralateral
- decussate in spinal cord
- nondiscriminate sensations (pain, temp, pressure)
- through the thalamus to the primary somatosensory cortex
major descending pathways
pyramidal tracts:
- lateral corticospinal
- ventral (anterior) corticospinal
extrapyramidal tracts
- rubrospinal tract
what do major descending pathways synapse with
ventral (anterior) horn interneurons
lateral corticospinal pathways
- cross in pyramids of medulla
- voluntary motor to limb muscles
ventral (anterior) corticospinal pathways
- cross at spinal cord
- voluntary to axial muscles
