Spinal Cord Ascending System : (DCP and STT) Flashcards
Information carried by the Dorsal Column Pathway
2-point discrimination
vibration sense
proprioception (helps you know where your hands and limbs are in the dark)
Receptors for DCP
2 point discrimination: Meissner’s corpuscle
Vibration: Pacinian Corpuscle
Joint position: Joint receptors
morphology of midbrain cross section:
upside mickey mouse called cerebral peduncles
cerebral peduncles
they connect the midbrain to the cerebral cortex
substantia naigra
blacks substance found in the midbrain.
produces dopamine
responsible for Parkinson’s when it is damaged
Pathway of information via the DCP
first order fibers: synapse in the nucleus cuneatus in medulla
second order fibers: (travels through the medial lemniscus) synapse in the thalamus
third order fibers: synapse in area 312 of the cortex
where in the central cortex is most of the sensory information located?
Postcentral Gyrus
Pre central Gyrus
Motor information
Area 4
precentral gyrus
area 312
postcentral gyrus
area 17
vision
functional component carried in DCP
GSA
What senses position, vibration and pain in the head?
Trigeminal ganglion
DCP does not sense pain and vibration, proprioception in the head
nucleus cuneatus
nucleus in the medulla where the first order axons from upper limb synapse.
No fascilculus cuneatus after T6.
medial lemniscus (ribbon)
made up of thousands of axons from DCP that pile up in the midline of the medulla.
nucleus of second order axons
Ventral Posterior Lateral nucleus. (VPL)
Location: thalamus
stroke/injury to the right thalamus
loss of sensation on the left side (opposite side)
knife wound on the right side of the spinal cord (DCP)
loss of sensation on the right side (same side)
third order axons termination
area 312 of the post central gyrus.
location: cortex
internal arcuate fibers
name for the fibers of second order fibers
crosses the midline
nucleus gracilis
handles lower limb sensory information.
location: medulla.
The rest of the lower limb DCP is the same as upper limb.
fasciculus cuneatus
first order neurons that transmits information from C1-T6 to the medulla.
used by DCP and Dorsal spinocerebellar tract
location: spinal cord (C1-T6).
fasciculus cuneatus vs nucleus cuneatus
fasciculus cuneatus: axons located in the spinal cord
nucleus cuneatus: cell bodies located in the medulla
Tabes Dorsalis
wipes out the dorsal column pathway
Positive Romberg’s sign
Loss of proprioception: patients cannot stand steadily when their eyes are closed.
Indicates problems with DCP
Draw the DCP
Draw the damn thing
Spinothalamic Tract (STT)
classic PAIN pathway.
Pathway of Spinothalamic tract
first order synapse in Nucleus Proprius of Spinal Cord.
Second order fibers cross the midline at spinal cord and synapse in the VPL
3rd order fibers synapse in Area 312 of the cortex
Laterality of DCP
contralateral once it crosses midline at medulla.
crosses midline at medullary level
Laterality of Spinothalamic tract
contralateral at spinal cord level.
Crosses midline at spinal cord level
myelination of pain sensory fibers
lightly myelinated: enter spinal cord via LATERAL DiVISION
Lateral Division of Dorsal Root Afferent
Entrance of:
Pain fibers
Temperature
Light Touch
visceral afferents
lesion of DCP at spinal cord level
ipsilateral: loss of sensation on the same side of the body
lesion of DCP at the brain
contralateral: loss of sensation on the opposite side
lesion of Spinothalamic tract at spinal cord level
contralateral: loss of sensation on the opposite side of the body.
lesion of spinothalamic tract at brain level
contralateral loss of sensation
Syphilis
Wipes out posterior column (of Dorsal Column Pathway) and Dorsal Root Ganglion
