6. Somatosensory system II Flashcards
(30 cards)
which is more lateral:
gracile or cuneate tract?
cuneate
where is the primary somatosensory cortex located? (numbers)
1,2,3
where is the primary motor cortex located? (numbers)
4
what is the name of the structure where the somatosensory cortex is located?
post central gyrus
what info is carried in the cuneate tract?
info from upper body
what order are the neurones which project from the VP complex of thalamus to the S1 region ?
third order
4 types of afferent nerve fibres - thinnest to thickest
- C
- Adelta
- A beta
- A alpha
what does DCML stand for
Dorsal column medial lemniscus
what does the DCML process?
innocuous touch from skin and joint receptors
2 tracts of DCML - describe what they are
Cuneate tract - upper body + limbs - rostral to T6
Gracile tract - lower body + limbs - caudal to T6
which 2 places do the axons in the DCML synapse?
- caudal medulla
2. Ventral posterior lateral nuclei of thalamus
where do they tracts decussate in the DCML?
caudal medulla
when do the tracts in the DCML become the medial lemniscus ?
after decussating
which lobe is the primary somatosensory cortex 1,2,3, lcated?
parietal
tract which carries innocious info from the face?
trigeminothalamic
3 divisions of the trigeminal nerve
- opthalmic
- mandibular
- maxillary
2 places where axons in trigeminothalamic synapse?
- trigeminal complex nucleus
2. Ventral Posterior medial nucleus of thalamus
where do axons in the trigeminothalamic tract decussate?
trigeminal complex nucleus
difference between innocous and nociceptive pathways?
nociceptive axons decussate in the spinal cord rather than caudal medulla
where do 1st neurones synapse first in the proprioceptive pathways of both the upper and lower body?
dorsal and ventral horns at the spinal cord
difference between proprioceptive pathways of the upper and lower body?
lower body has extra synpase at Clarke’s nucleus in the thoracic spinal cord - this axon ascends as the spinocerebellar tract which is more lateral than the upper body
where does decussation occur in the proprioceptive pathways ?
VPL nucleus of the thalamus
what is the primary sensory processing area?
postcentral gyrus
what is the secondary sensory processing area?
posterior parietal
