-
All paths lead to:
lower motor neuron
-
What is the function of motor control systems?
tell LMN (alpha and gamma MN) what to do
-
What is the end result of motor control systems?
instruct LMN to fire or not to fire
-
How many motor control systems are there?
2
-
What are the names of the motor control systems?
-
Are the motor control systems integrated?
yes, highly integrated (play off each other and can't work alone!)
-
Describe the pyramidal motor control system:
initiated, voluntary skeletal muscle activity
-
Describe the extrapyramidal motor control system:
involuntary skeletal muscle activity (instinctive, reflexive)
-
What are both motor control systems trying to get the attention of?
LMN
-
Which motor control system is the supplemental motor area a part of?
pyramidal system
-
In which lobe is the supplemental motor area located?
frontal lobe
-
The supplemental motor area is anterior to:
pre-central gyrus (PCG)
-
The supplemental motor area is superior to:
pre-motor cortex
-
What is the supplemental motor area functionally?
an association area
-
What are association areas?
interact with pre-central gyrus using association fibers
-
What is the supplemental motor area important for?
initiation of movement
-
The supplemental motor area is involved with:
orientation of eyes and head (extrinsic eye m coordination)
-
What does the supplemental motor area plan?
sequential and bi-manual movements (like tying shoes)
-
What does the supplemental motor area interact with?
pre-central gyrus
-
Where does the supplemental motor area send UMN to?
- association areas
- cranial N mtor nuclei
- ventral horns of SC where UMN synapse with LMN
-
When the supplemental motor area sends UMN to CN motor nuclei, which tract does it use?
corticobulbar
-
When the supplemental motor area sends UMN to ventral horns of SC, which tract does it use?
corticospinal tract
-
The supplemental motor area sends UMN to ventral horns of SC where UMN synapse with LMN. Where does the LMN go to?
skeletal mm
-
What is the main function of supplemental motor area?
finesse what precentral gyrus does
-
Which system is the pre-motor area a part of?
pyramidal system
-
Which lobe is the pre-motor area in?
frontal lobe
-
The pre-motor area is anterior to:
precentral gyrus
-
What is the pre-motor area functionally?
association area
-
What does the pre-motor area control?
trunk, pelvic, and pectoral girdle musculature (changing posture; stabilization)
-
What is the pre-motor area involved with?
anticipatory postural control and adjustments
-
What does the pre-motor area interact with?
- pre-central gyrus
- UMN to CN motor nuclei in brain stem UMN to ventral horns (SC) via corticospinal
-
Which system is the broca's area a part of?
pyramidal system
-
Which lobe is the broca's area located in?
frontal lobe
-
What is the Broca's area anterior to?
precentral gyrus (in area of pre-motor cortex)
-
What is the Broca's area functionally?
association area
-
What is the primary function of the Broca's area?
instigate speech
-
What are the types of motor tracts?
- corticofugal
- cranial nerve tracts
- modulatory descending motor tracts
-
Are corticofugal motor tracts LMNs or UMNs?
UMN
-
How many types of corticofugal tracts are there?
2
-
What are the 2 types of corticofugal tracts?
- corticospinal
- corticobulbar
-
Which motor control system is the corticospinal tract a part of?
pyramidal system
-
What does the corticospinal tract control?
voluntary contralateral skeletal muscle activity from the extremities and trunk
-
Is the corticospinal tract bilateral or unilateral?
unilateral
-
How many neurons make up the corticospinal tract?
2 neuron pathway
-
Where are the cell bodies of the UMNs of the corticospinal tract located?
pre-central gyrus (primary motor cortex) of frontal lobe
-
Where do the UMNs that collectively form the corticospinal tract go?
- descend through posterior limb of internal capsule (PLIC)
- through crus cerebri of cerebral peduncles of midbrain
- through ventral pons (longitudinal fibers) and into ventral medulla
-
What happens after the UMNs of the corticospinal tract reach the medulla?
- 90% decussate in pyramids of medulla
- 10% do not decussate in the pyramids
-
Where do the 90% of UMNs in the corticospinal tract that decussate in the pyramids of the medulla descend?
contralateral lateral white column of SC
-
What are the 90% of UMNs in the corticospinal tract that decussate in the pyramids of the medulla called as they descend?
lateral corticospinal tract
-
Where do the lateral corticospinal tract fibers synapse with LMNs?
ventral horn
-
Where do the 10% of UMNs in the corticospinal tract that don't decussate in the pyramids go?
continue ipsilateral descent via ventral white column of the SC
-
What are 10% of UMNs in the corticospinal tract that don't decussate in the pyramids called as they descend?
ventral corticospinal tract
-
Where does the ventral corticospinal tract decssate?
via anterior white commissure (ventral spinal cord) to contralateral side
-
Where do the ventral corticospinal tract fibers synapse with LMN?
ventral horn
-
Where do the LMN go?
out through spinal nerve to innervate skeletal mm via peripheral nn
-
As a result of the 90/10 decussation pattern, the corticospinal tract never experiences:
a complete lesion
-
Stroke via R anterior cerebral artery will damage:
- UMN in R hemisphere
- contralateral effect=problems on the L side of the body
-
Spinal cord accident that wipes out the corticospinal tract in the spinal cord on L side:
ipsilateral effect=problems on L side of body
-
How do you refer to tracts when it comes to injuries?
either corticospinal tract on R side of spinal cord (and vice versa)
|
|
