block 5 lecture 6 sensory systems Flashcards
how long is the spinal cord?
42cm-45cm
where does the spinal cord start and finish?
foramen magnum to L1/L2
what are the three layers of connective tissue covering the spinal cord?
pia, archnoid and dura mata
whats the difference between epidural space on brain and spinal cord?
at the brain its a potential space, at the spinal cord its an actual space
what does the epidural space of the spinal cord contain?
internal venus plexus and fat
what does the subarachnoid space contain?
cerebrospinal fluid
where are the two enlargements of the spinal cord?
cervical and lumbar region
what are the enlargements in the spine due to?
increase of pathways to innovate the limbs
what are the two roots that come out of spinal segments?
dorsal and ventral
what information is transmitted via dorsal roots?
sensory
what information is transmitted via ventralroots?
motor
where are spinal roots found?
in between in vertebral foramen and spinal cord tissue
what do spinal nerves bifurcate into?
ventral and dorsal ramus
why dosent the spinal nerve go to the bottom of the vertebra?
during development at three months the spinal cord is the same length of the vertebral column, after this the vertebral column growth over shoot that of the spinal cord.
what happens at the bottom of the spinal cord?
tapering this is the conus medullaris at L1/L2
what is the cauda equina?
roots below the canus medullaris bunch together in the sub arachnoid space
where do you find spinal nerves?
intervetebral foramina
what are the segments of the spinal cord?
cervical, thoracic, lumbar and sacral
what runs down from the cernus medullaris?
cauda equina
what is the continuation of the pia mata called?
filum terminale
what is a cistern?
anatomical lake of cerebrospinal fluid`
what changes about the white matter as you go down the spinal cord?
white matter is reduced
shape of grey matter in the spinal cord?
has a H shape, anterior and posterior horns, there is a central canal
what are the anterior horns responsible for?
motor
what are the posterior horns responsible for?
sensery
what is the groove at the front called?
median fissure
where do you get lateral horns and what is there purpose?
thoracic and the autonomic region
what is a commissure?
an axon which crosses from one side of the CNS to another
what is decassation?
crossing the midline
how many pathways are there for ascending tracts? (information coming into the CNS)
3: 1st order, 2nd order and 3rd order
aspects of the 1st order neurons?
they run through dorsal roots
the cell bodies are in the dorsal root ganglia
from external receptors
aspects of the 2nd order neurons?
spinal cord and brain stem tracts
decassate
aspects of the 3rd order neurons?
run from the thalamus to the sensory corten via the internal capsule
conscious perception pathways?
dorsal column and spinalthalamic
unconscious perception pathways?
spinocerebellar, spinorectal, spinoreticular and spino-olvary
what do we test clinically when testing the spinal cord?
conscious perception
in dorsal column where do 1st order neurons enter the spinal cord?
dorsal roots
in dorsal column how do the 1st order neurons ascend?
ipsilaterally
in dorsal column where do the 1st order neurons synapse?
gracile nuclei and cuneate nuclei
in dorsal column what are the fibers that run in the gracile nucleus called? and what do they represent?
fasiculus gracalis and the lower half of the body
in dorsal column what are the fibers that run in the cunate nucleus called? and what do they represent?
fasiculus cuneatus found in the upper part of the spinal cord as they contain information from the upper half
in dorsal column where do 2nd order neurons come through and where do they go?
come from nucleus and cross over the bran stem and form medial lemnisous
in dorsal column where does the medial lemniscus run to?
contralateral thalamus
in dorsal column where do third order neurons run from and to?
from the contralateral thelemus and goes to the cerebral cortex
what is the column medial lemniscus pathway important for?
discriminating aspects of touch and proprioception
what is it called when you have a lack of the column medial lemniscus pathway?
sensory ataxia
in spinothalamic tracts where does it go from and to?
spinal cord to the thalamus
in spinothalamic tracts where do 1st order neurons come from and synapse?
they come from limbs and synapse with lissors tracts/ dorso lateral faliculous
in spinothalamic tracts what heppens to this information in the spinal corn?
raises 1-2 segments
what are 2nd order neurons of the lateral spinothalamic joined by? and where?
trigeminothalamic tract in the brain stem
what is the region called that keeps you awake?
reticular formation
in spinothalamic tracts what is the signals in this pathway?
crude touch, pain and temperature
what are the two pathways of spinocerebellar tracts?
dorsal spinocerebellar pathway and the ventral spinocerebellar pathway
in spinocerebellar pathway how does the dorsal information rise?
ipsilaterally
in spinocerebellar pathway what happens to the ventral information?
ventral enters the spinal cord and decessates immediately
in spinocerebellar pathway what is venral responsible for?
movement control
in spino-olivary what is the location and what is it for?
spinal cord to the accessory olivary nuclei and cerebellum
for movement co-ordination associated balance
in spinoectal what is the location and what is it for?
spinal cord to superior calliculi
for reflex of turning head and eyes to stimulation
in spinoreticular what is the location and what is it for?
spinal cord to reticular conductinf system
arrouing consciousness through cutaneous stimulation
