4-Motor II Flashcards
corticotectal tract starts/ends
og @ occipital lobe (visual association cortex)
terminates @ superior solliculus (midbrain) and oculomotor accessory nuclei (midbrain)
tectospinal tract starts/ends
og @ superior colliculus
terminates @ C and T spinal cord levels
aka picks up from corticotectal tract
tectospinal tract function
reflex moves of eyes, neck, upper thorax in resp to visual/auditory/vestibular/cutaneous startling stimuli
pyramidal cells contribute to what tracts
- corticonuclear
- corticorubral
- corticopontine
- corticoreticular
- corticospinal
for conscious voluntary move
which tracts do subconscious involuntary control
reticulospinal, vestibulospinal
for background muscular activity to cont modulate muscle tone, posture, balance
corticorubral tract start/end
og @ motor cortex
terminate @ red nucleus in midbrain
rubrospinal tract start/end
og @ red nucleus
terminate @ cervical spinal cord
picks up corticorubral
rubrospinal tract function
excitatory to distal flexor muscles of the UL (hand, digits)
not significant in humans but can allow retain function of distal UL if CST damaged
corticoreticular tract start/end
og @ motor cortex
terminate @ brain stem reticular formation nuclei in pons and medulla
reticulospinal tracts
RST
- medial/pontine
- lateral/medullary
modulate muscle tone and posture maintenance by synapsing with gamma motor neurons
medial RST
og @ RF in pons
terminate at all spinal cord levels
excitatory to motor neurons for paravertebral and limb extensors (antigravity muscles) aka for standing
lateral RST
og @ RF in medulla
terminates @ all spinal cord levels
inhibitory to motor neurons for paravertebral and limb extensors (antigravity) aka for lying down
vestibulospinal tracts
VST
- lateral VST
- medial VST
lateral VST
og @ lateral vestibular nucleus
terminates @ all levels
excitatory for trunk paravertebral and proximal limb extensors (antigravity) like Medial RST
+elicit automatic reflex resp to modulate tone so when loosing balance tract will adjust to regain upright posture
medial VST
og @ medial vestibular nucleus
terminates @ C and upper T levels to inn neck muscle
coordinates head and eye move during gaze
functional classification of descending motor pathways
- ventromedial/anteromedial
- lateral
- cortical
cortical group
only axons of lateral corticospinal tract (to inn distal limb muscles/hand)
distinct, fractionated moves of digits like playing piano, exquisite motor control
lateral group
- lateral corticospinal tract
- rubrospinal tract
distal muscles limb (to control digits) esp hand
anteromedial group
- anterior corticospinal
- medial and lateral vestibulospinal
- medial and lateral reticulospinal
- tectospinal
maintain balance for posture via gross moves of axial/trunk and proximal limb
poliomyelitis
viral infection of spinal cord LMN so get LMN lesion signs
combined systems disease
aka subacute combined degeneration or posterolateral sclerosis
-loss of vibratory, proprioception, touch, discrim
-show UMN lesion signs
from B12 def so abnormal FAs > abnormal myelin
-degen of FG + FC + CST
part of spinal cord most susceptible to occlusions
cervical bc no anastomoses with radicular A’s like thoracic, lumbar, and sacral
-only spinal A’s
