Spinal Cord Ascending Systems Flashcards
What information is relayed on the dorsal column pathway (DCP)?
Proprioception
2 Point Discrimination
Vibration Sense
GSA function
What are the fast adapting receptors?
Hair Follicle
Meissner’s Corpuscle
Pacinian Corpuscle
What are the slow reacting receptors?
Free Nerve Endings Merkel's Disk Ruffini Ending Joint Receptor Neuromuscular Spindle Golgi Tendon Organs
What do free nerve endings detect?
Pain and Temperature
What do Merkel’s Disk detect?
Touch
What do hair follicles detect?
Touch
What do Meissner’s Corpuscles detect?
2 point discrimination
What do Pacinian Corpuscles detect?
Vibration
What do joint receptors detect?
Joint Position
What do neuromuscular spindles detect?
Limb and muscle stretch
What do Golgi Tendon Organs detect?
Muscle tension
What do Ruffini Corpuscles detect?
Stretch and pressure
Describe the pathway of the DCP.
Receptors ->
Gray Matter ->
Fasciculus Gracilis (medial - lower body) OR Fasciculus Cuneatus (lateral - upper body) ->
Nucleus Gracilis/Cuneatus (SYNAPSE) ->
Thalamus as the Ventral Posterolateral Nucleus (SYNAPSE)
What are other names for the motor cortex?
Area 4
Precentral Gyrus
What are other names for the sensory cortex?
Area 312
Postcentral Gyrus
Descibe the 3 orders of neurons in the DCP.
1st Order - go from the limb to the nucleus cuneatus/gracilis and synapse
2nd Order - cross the midline through the medial lemniscus and synapse at the VPL in the thalamus
3rd Order - synapse on the post central gyrus of the sensory cortex
What are the fibers to the medial lemniscus that cross the midline called?
Internal Arcuate
What is Romberg’s sign (tabes dorsalis)?
It is positive if patient requires vision to stand. It appears positive in sensory ataxia.
Describe the pathway of the spinothalamic tract.
Receptors ->
Gray Matter (SYNAPSE) crosses midline ->
Neospinothalamic Tract ->
Thalamus at the VPS (SYNAPSE)
Describe the effects of syringomyelia.
As the tub expands in the spinal cord, it will hit the STT and affect the arms first and move downwards.
What are the effects of the Brown-Sequard lesion?
Pain and temperature sensation are lost from the opposite side of the lesion and proprioception from the same side.
What do the spinocerebellar tracts detect?
Unconscious proprioception
Where are the spinocerebellar tracts located?
On the very lateral part of the white matter
What do the spinocerebellar tracts arise from?
Clark’s Nucleus (Nucleus Dorsalis)
What information do the spinocerebellar tracts relay?
Muscle Stretch
Describe the path of the dorsal spinocerebellar tract.
Receptor -> Nucleus Dorsalis in the Gray Matter (SYNAPSE) -> DSCT in White Matter -> Inferior Cerebellar Peduncle -> Cerebellum (SYNAPSE)
Describe the path of the cuneocerebellar tract.
Receptor -> Gray Matter -> Fasciculus Cuneatus -> Accessory Cuneate Nucleus (SYNAPSE) -> Inferior Cerebellar Peduncle -> Cerebellum (SYNAPSE)
Where is the DSCT located?
At the levels of C8 - L2
What is the function of the ventral spinocerebellar tract?
It monitors the activity of the interneurons in the gray matter and relays the information to the cerebellum
What is the pathway of the VSCT?
Gray Matter (crosses midline) ->
VSCT on White Matter) ->
Superior Cerebellar Peduncle (crosses midline ->
Cerebellum (SYNAPSE)
