Somatosensory Ascending Pathway - Part II Flashcards
(76 cards)
Why do you feel “funny” when your funny bone gets irritated?
Ulnar nerve: Meissner Corpuscle causes tingling sensation
What does the DCML synapse with? Where?
2nd order neurons in Clarke’s nucleus
Where is Clarke’s nucleus?
lamina 7
What does the DCML do?
fine touch, vibration, proprioception
- participates in spinal reflex
What are the type of joint capsule receptors in the posterior root ganglion of the DCML?
Ia, Ib
- Ia most posteriorly, proproception, muscle spindle
- Ib from GTO
What are 1st order neurons in the DCML?
- cell body location
- located at dorsal root ganglia
What are AB receptors for in the DCML?
for meissner corpuscle, Pacini corpusle, Ruffini ending, Merkle cell, etc.
- conduct to more medial, anterior compared to proprioception part
What does lamina 7 form?
synapse where 2nd order neuron for posterior spinocerebellar trat and anterior spinocerebellar tract
Where is Clarke’s nucleus?
Lamina 7
What are the components of the Dorsal Column?
- fasciculus gracilis below T6
- fasciculus cunetus above T6
- lissauer’s tract
- fasciculus interfascicularis (b/w FG and FC)
- septomarginal fascuiculus
What does the fasciculus interfascicularis and septomarginal fasciculus do?
visceral and some somatic pain pathways
What kind of tracts are in the septomarginal fasciculus and fasciculus interfascicularis?
ascending tracts for visceral pain
What is the pathway of Lissauer’s tract?
ascend to C2 level of spinal cord, continue to be spinal trigeminal tract for trigeminal nerve functions
Is somatotopy maintained in the DCMLs pathway?
Yes
What are the third order neurons of the DCML?
- ventral posterolateral nucleus of the thalamus
What are the two parts of the ventral posterolateral nucleus of the thalamus?
- shell: proprioception (outside of VPL)
- core: vibration and fine touch (inside VPL)
Where do the parts of the VPL project?
to S1
Where are the 2nd order neurons of the DCML?
caudal medulla
What are the 2nd order neurons for the DCML? Where is sensory decussation?
- fasciculus gracilis: gracile nnucleus
- fasciculus cuneatus: cineate nucleus
- sensory decussation in internal arcuate fibers of medial leminiscus
What is the 1st order neuron of the trigeminothalamic pathway?
- trigeminal ganglion and mesencephalic nucleus
What is the trigeminal ganglion for?
fine touch, vibration, and proprioception
- outside of dura matter in medial cranial fossa
What is the messencephalic nucleus for? Location?
PNS structure, proprioception (CN V)
- located at CNS, midbrain but part of PNS
Where does the mesencephalic nucleus project to?
CN V motor nucleus for myotatic reflex
What reflex is mesencephalic nucleus responsible for?
CN V = tongue depressor flip - close jaw