Descending Motor System (Exam 1) Flashcards
1
Q
What does paresis mean?
A
weakness (partial)
2
Q
What does plegia mean?
A
No voluntary movement
3
Q
What does paralysis mean?
A
No voluntary movement
4
Q
What does palsy mean?
A
Weakness or no movement
5
Q
What does hemi mean?
A
one side of the body
6
Q
What does para mean?
A
both legs
7
Q
What does mono mean?
A
one limb
8
Q
What doe di mean?
A
both sides of body equally affected
9
Q
What does quadri or tetra mean?
A
all four limbs
10
Q
Where are the cell bodies located for upper motor neuron?
A
cortex or brainstem
11
Q
Where does the upper motor neuron project to?
A
Descend within the CNS to govern activity of lower motor neuron cell bodies
12
Q
Where are cell bodies located for lower motor neuron?
A
Spinal cord and brainstem
13
Q
Where does the lower motor neuron projects to?
A
Muscles in the periphery
14
Q
What is the criteria to be considered an Alpha motor neruon?
A
-Large cell body
- Target skeletal muscle
15
Q
What is the criteria to be considered a Gamma motor neuron?
A
- Smaller axon diameter
- Target muscle spindles to help control stretch reflex
16
Q
What is the criteria to be considered a Beta motor neuron?
A
- Fewer in number
- Innervate both muscles both within and outside of the muscle spindle
17
Q
Where do lateral motor system UMN descend and synapse?
A
- Lateral column of the spinal cord
- Synapse on lateral ventral horn motor neurons (LMN) and interneurons
18
Q
What muscles does the lateral motor system target?
A
distal limb muscles
19
Q
Where do the medial motor system UMN descend and synapse?
A
- Descend in the anteromedial columns of the spinal cord
- Synapse on medial ventral horn motor neurons (LMN) and interneurons
20
Q
What muscles does the medial motor system target?
A
Proximal axial muscle
21
Q
What tracts are within the lateral motor system?
A
- Lateral Corticospinal Tract
- Rubrospinal Tract
22
Q
What tracts are within the Medial Motor System?
A
- Anterior Corticospinal Tract
- Vestibulospinal Tract
- Reticulopsinal Tract
- Tectospinal Tract
23
Q
Where do pyramidal tract originate and terminate?
A
- Originate in cortex
- Terminate on LMN cell bodies in brainstem (CNN) & spinal cord (anterior horn)
24
Q
What does pyramidal tract control?
A
Volitional movement
25
Where do extrapyramidal tract originate and terminate?
- Originate in brainstem
-Terminate in spinal cord (LMN)
26
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
27
Which of the lateral motor systems are pyramidal?
Lateral corticospinal tract
28
Which of the lateral motor system are extrapyramidal?
Rubrospinal Tract
29
Which of the medial motor system tracts are pyramidal?
Anterior Corticospinal Tract
30
Which of the medial motor system are extrapyramidal?
Vestibulospinal Tract
- Reticulospinal Tract
- Tectospinal tract
31
What is the origin of the lateral corticospinal tract?
Primary motor cortex and other frontal & parietal areas
32
Where is the decussation of the lateral corticospinal tract?
Pyramidal decussation at cervicomedullary junction
33
Where is the level of termination of the lateral corticospinal tract?
- Lateral ventral horn
- Entire cord
34
What is the function of the lateral corticospinal tract?
Volitional movement of contralateral limbs
35
What fibers make up the Corticobulbar Tract?
Fibers project from the cortex to the brainstem
36
Where is CN V (trigeminal - muscles of mastication) located?
Upper pons
37
Where is CN VI (facial- lower facial muscles) located?
Lower pons
38
Where is the CN XII (hypoglossal - tongue protrusion) located?
medulla
39
Where is the origin of the rubrospinal tract?
Red nucleus
40
Where does the decussation of the rubrospinal tract occur?
Ventral tegmental decussation (midbrain)
41
Where is the level of termination of the rubrospinal tract?
- Lateral ventral horn & intermediate zone
- Cervical cord
42
What is the function of the rubrospinal tract?
- Movement of contralateral upper limb
- Function uncertain in humans
43
Lesions to the corticospinal tract above the red nucleus cause what posture?
Decorticate (flexor)
44
Lesions to the corticospinal tract below the red nucleus cause what posture?
Decerebrate (extensor)
45
Where does the anterior corticospinal tract originate?
Primary motor cortex and supplementary motor area
46
Where does the decussation of the anterior corticospinal tract occur?
-Some remain ipsilateral
- Some cross in the ventral white commissure of the spinal cord
47
Where is the level of termination of the anterior corticospinal tract?
Cervical and upper thoracic cord
48
What is the function of the anterior corticospinal tract?
Bilateral axial & girdle muscles
49
What is the origin of the medial vestibulospinal tract?
Medial & inferior vestibular nuclei
50
Where does decussation of the medial vestibulospinal tract occur?
Descends bilaterally
51
Where is the level of termination of the medial vestibulospinal tract occur?
Cervical & upper thoracic cord
52
What is the function of the medial vestibulospinal tract?
Positioning of the head and neck
53
Where is the origin of the lateral vestibulospinal tract?
Lateral vestibular nucleus
54
Where does the decussation of the lateral vestibulospinal tract occur?
Does not cross
55
Where does the lateral vestibulospinal tract terminate?
Enter cord
56
What is the function of the lateral vestibulospinal tract?
balance
57
Where does the medial vestibulospinal tract receive input from?
Semicircular canals (rotation)
58
What does the medial vestibulospinal tract target, muscles does it activate and do?
- Neck and proximal shoulder muscles
- Activate extensors
- Align head with body
59
Where does the lateral vestibulospinal tract receive input from?
Primarily from otoliths (gravity and linear acceleration)
60
What does the lateral vestibulospinal tract target, muscles does it activate and do?
- Proximal limb and trunk muscles
- Activate extensors & inhibits flexors
- Postural alignment & balance
61
What do both medial and lateral vestibulospinal tract do?
- Activate postural extensors (antigravity muscles- involuntary)
- Compensatory feedback response to postural instability detected by vestibular system
62
Where does the reticulospinal tract originate?
Pontine & medullary reticular formation
63
Where does the decussation of the reticulospinal tract occur?
Does not cross
64
Where is the level of termination of the reticulospinal tract occur?
Entire cord
65
What is the function of the reticulospinal tract?
Automatic posture and gait related movements
66
Where does the reticular formation receive input from?
Cortex, hypothalamus, & brainstem
67
What does the reticulospinal tract initiate?
- Feedfoward adjustments to stabilize posture with planned movement
- Assists with temporal & spatial coordination of limb & trunk movement
68
Where does the tectospinal tract originate?
Superior colliculus (in tectum)
69
Where does the decussation of the tectospinal tract occur?
Dorsal tegmental decussation
70
Where does the tectospinal tract terminate?
Cervical cord
71
What is the function of the tectospinal tract?
Coordination of head and eye movement
72
What does the tectospinal tract allow?
Coordination of head and neck movements to orient towards visual stimuli
73
What does the sympathetic part of the autonomic nervous system have?
- T1-L2 (or L3)
- Fight or flight
74
What does the parasympathetic part of the autonomic nervous system have?
- CNN and S2-S4
- Rest and digest
75
Where do preganglionic neurons travel in the sympathetic nervous system?
- Paired paraverterbal ganglia which runs from cervical to sacral levels
- Unpaired preverterbal ganglia
76
Where do postganglionic neurons travel to in the sympathetic nervous system?
Distance to effector organ
77
What do preganglionic neurons release in sympathetic nervous system?
Acetylcholine
78
What do postganglonic neurons release in sympathetic nervous system?
Norepinephrine
79
Where do preganglionic neurons in the parasympathetic nervous system travel to and release?
- Travel long distance to terminal ganglia
- Release acetylcholine
80
Where do postganglionic neurons in the parasympathetic nervous system travel to and release?
- Travel short distance to effector organ
- Release primarily acetylcholine
81
What other things give input to the autonomic nervous system?
- Hypothalamus
- Brainstem nuclei
- Amygdala
- Limbic cortex
- Sensory afferents
- Internal receptors
82
What causes autonomic dysreflexia?
Caused by disconnect between the brain and the sympathetic neurons in the thoracolumbar spine
83
