Descending Motor System (Exam 1) Flashcards
What does paresis mean?
weakness (partial)
What does plegia mean?
No voluntary movement
What does paralysis mean?
No voluntary movement
What does palsy mean?
Weakness or no movement
What does hemi mean?
one side of the body
What does para mean?
both legs
What does mono mean?
one limb
What doe di mean?
both sides of body equally affected
What does quadri or tetra mean?
all four limbs
Where are the cell bodies located for upper motor neuron?
cortex or brainstem
Where does the upper motor neuron project to?
Descend within the CNS to govern activity of lower motor neuron cell bodies
Where are cell bodies located for lower motor neuron?
Spinal cord and brainstem
Where does the lower motor neuron projects to?
Muscles in the periphery
What is the criteria to be considered an Alpha motor neruon?
-Large cell body
- Target skeletal muscle
What is the criteria to be considered a Gamma motor neuron?
- Smaller axon diameter
- Target muscle spindles to help control stretch reflex
What is the criteria to be considered a Beta motor neuron?
- Fewer in number
- Innervate both muscles both within and outside of the muscle spindle
Where do lateral motor system UMN descend and synapse?
- Lateral column of the spinal cord
- Synapse on lateral ventral horn motor neurons (LMN) and interneurons
What muscles does the lateral motor system target?
distal limb muscles
Where do the medial motor system UMN descend and synapse?
- Descend in the anteromedial columns of the spinal cord
- Synapse on medial ventral horn motor neurons (LMN) and interneurons
What muscles does the medial motor system target?
Proximal axial muscle
What tracts are within the lateral motor system?
- Lateral Corticospinal Tract
- Rubrospinal Tract
What tracts are within the Medial Motor System?
- Anterior Corticospinal Tract
- Vestibulospinal Tract
- Reticulopsinal Tract
- Tectospinal Tract
Where do pyramidal tract originate and terminate?
- Originate in cortex
- Terminate on LMN cell bodies in brainstem (CNN) & spinal cord (anterior horn)
What does pyramidal tract control?
Volitional movement
Where do extrapyramidal tract originate and terminate?
- Originate in brainstem
-Terminate in spinal cord (LMN)
Extrapyramidal tracts are are modulated by and what do they control?
- Modulated by other inputs
- Control involuntary & automatic control of muscle tone, balance, posture & modulation of motor plans
Which of the lateral motor systems are pyramidal?
Lateral corticospinal tract
Which of the lateral motor system are extrapyramidal?
Rubrospinal Tract
Which of the medial motor system tracts are pyramidal?
Anterior Corticospinal Tract
Which of the medial motor system are extrapyramidal?
Vestibulospinal Tract
- Reticulospinal Tract
- Tectospinal tract
What is the origin of the lateral corticospinal tract?
Primary motor cortex and other frontal & parietal areas
Where is the decussation of the lateral corticospinal tract?
Pyramidal decussation at cervicomedullary junction
Where is the level of termination of the lateral corticospinal tract?
- Lateral ventral horn
- Entire cord