Test 3 - Ch. 14 Flashcards
Where are cell bodies of UMN located?
cerebral cortex and BS
cerebral cortex - director
BS - laborer
What structure sends the message of plan to move to cortex and BS?
BG
What are the two places the UMN communicate to?
Axons to BS and SC
What are the three tracts of the medial motor tract?
reticulospinal
vestibulospinal
*lateral vestibulospinal
corticospinal
reticulospinal tract
Pick stuff up - more in arms
involuntary gross movements
origin of medial BS UMN pathway
Vestibulospinal tract- medial
upright against gravity - more in lower body
upper trunk, head and neck
lower degree of voluntary control
vestibulospinal tract- lateral
UNILATERAL PROJECTION
axial and lower extremity extensors
rest of Mm up against gravity
lower degree of control
Medial corticospinal tract
Voluntary control of neck, shoulder and trunk Mm
project to medial motor pools bilaterally
makes movement functional
What are the lateral tracts?
rubrospinal
lateral corticospinal
rubrospinal tract
distal extensors
red nucleus-spine
project distally
minor control
lateral corticospinal
directly activates distal movements *** most important Fractionated movement direct control of LMN guiding control to BS
Describe non-specific motor tracts
descend from BS - lower threshold for all other motor neurons so upper can start lower, increase AP
turned on by activity of limbic
Job of corticobrainstem
UMN of cranial Nn
Job of cortical motor
med and lat corticospinal homebase
pre-central gyrus of frontal lobe
Job of pre-motor area
anticipatory postural control
Job of supplementary motor area
plan bimanual and activities that have sequence
3 signs of UMN lesions
- completely cut from LMN - SCI
- intact but tonically overactive - PD and TBI
- Cortical UMN damaged, BS okay - stroke
paralysis
no movement below injury, UMN still exists but no connection
paresis
some UMN cut = weakness
cortical UMN damaged but still connected to BS
What happens if a lateral corticospinal tract is damaged?
fractionated movement is lost
What happens to spinal reflexes below a cut to an UMN?
get stronger
babinski reflex
toes extend instead of flex
UMN cut
What is m stretch hyperflexia?
exaggerated reflex response to stretch
occurs when descending connection is missing or reduced
“velocity-dependent hypertonia”
increased reaction to quick stretch
norm stim = abnormally large response
Clonus
Rhythmic, repeating (usually involuntary) contraction of single muscle group
“velocity-dependent” that repeats itself
Clasp-knife
initial resistance then relax
What is myoplasticity?
Adaptive change w/in muscle itself
atrophy of disuse
stiffness
contracture
Temporary hypotonia
LMN go to sleep w/out UMN input
short time
“spinal shock”
wakes up = hyperactivity because no comm
velocity dependent hypertonia
1
"velocity-dependent" stretch reflex overactive muscle stretch hyperflexia "spasticity" = muscle stretch hyperflexia PD and BG damage
velocity independent hypertonia
2
UMN present but abnormally active PD and TBI too many signals always "rigidity" decorticate decerebrate
activity dependent hypertonia
3
BS active but cortex impaired
only occurs when trying to move
CVA
