Exam 2 - Somatosensation Flashcards
Aalpha
fastest
myelinated the most
motor to skeletal m., sensory from m. spindles and other proprioceptors
Abeta
fast
moderate myelination
non-noxious stimulus
Adelta
still fast
little myelination
discriminative pain ,temp
B
slower
little myelination
preganglionic autonomic
C
slowest
NO myelination
deep and visceral pain, temp, postganglionic autonomic
conscious somatosensation pathway
primary afferent (sensory)
sensory ganglion
interneuron
decussation
thalamic relay nuclei (LGN/MGN)
internal capsule
primary somatosensory cortex
DCML
specific vertebral segments
proprioceptive info from trunk/limbs to cerebral cortex (conscious)
C1-T5/6
T6-S3
C1-T5/6 DCML pathway
primary afferent
dorsal root ganglion
fasciculus cuneatus
nucleus cuneatus
internal arcuate fibers (decussation)
medial lemniscus
thalamic relay nucleus
internal capsule
primary somatosensory cortex
T6-S3 DCML pathway
primary afferent
fasciculus gracillis
nucleus gracillis
internal arcuate fibers (decussation)
medial lemniscus
thalamic relay nucleus
internal capsule
primary somatosensory cortex
clincal signs of proprioceptive deficits
dysmetria
wide-base stance or abnormal stance
circumduction
knuckling
stumbling
proprioceptors of DCML
skin mechanoreceptors
joint receptors
muscle spindles
golgi tendon organs
trigeminal system
touch sensation from face, oral cavity, nasal cavity
has 3 primary afferent in all 3 divisions (pain, touch, proprioception)
DCML
somatosensation of body - proprioception & touch
spinocervicothalamic tract (SCTT)
somatosensation of body - pain
spinoreticular tract (SRT)
somatosensation of body - pain
