spinal cord miscellaneous Flashcards
dorsal roots contain ___1___ fibers and ventral roots contain __2___ fibers
1 sensory/afferent
2 motor efferent
the central canal is continuous with what?
MO and 4th ventricle
the central canal expands inferiorly in the conus medullaris as what?
terminal ventricle
what is a funiculus?
a longitudinal bundle of white matter fibers that can be anatomically observed
the gray matter is a dense concentration of what?
neuron cell bodies
the white matter is a dense concentration of what?
neuron fibers (axons)
what gives the white appearance to white matter?
interfascicular oligodendrocytes which form myelin
bundles of functionally related axons within the funiculus are called?
fasciculi
what is the function of NCAMs or nerve cell adhesion molecules?
make sure axon carrying info ends up in the right tract and help keep fasciculi together
sensory input enters the spinal cord as what?and where?
as dorsal root ganglion axons at the dorsal lateral sulcus
where do most (not all) of the DRG axons synapse?
in the dorsal gray horn laminae
how many recognized fasciculi are there within the spinal cord?
over 2 dozen, we focused on half
which test involves standing with feet close together, arms out and eyes closed to check for balance?
Romberg’s test, most misinterpreted test we learn
these neurons originate in the spinal cord or brain stem and extend fibers into the PNS to innervate somatic musculature
lower motor neurons
these are neurons from higher brain centers that influence the LMN
upper motor neurons- corticospinal is a good example
UMN lesions would cause what?
- reduction or absence of voluntary movement
- hyperreflexia
- increased muscle tone
- clonus
- babinski sign
ex. cerebral palsy
LMN lesions would cause what?
- reduction or absence of voluntary movement
- hyporeflexia/ areflexia
- decreased muscle tone and atrophy
- muscle fibrillations and fasciculations
ex. polio
which UMN are involved with initiation of skilled voluntary movement?
pyramidal neurons
which UMN originate in the brain stem and extend down the cord and influence posture, muscle tone, enhance reflexes and thus allow voluntary movements to be smooth and effective?
extrapyramidal neurons
