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Semester 5 FSNM Exam 1 > Ch 10 - Motor Neurons > Flashcards

Ch 10 - Motor Neurons Flashcards

1
Q

Freedforward refers to

A

the anticipatory use of sensory information to prepare for movement
(like using visual info when driving)

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2
Q

Feedback refers to

A

the use of sensory information during or after movement to make corrections either to ongoing movement or to future movements (propioceptive and visual information)

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3
Q

LMS reside in

A

brainstem and spinal cord

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4
Q

Total resistance to muscle stretch is determiend by

A

active contraction, titin, and weak actin-myosin bonds

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5
Q

Muscle tone is the

A

resistance to stretch in a resting muscle

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6
Q

What is used clinically to assess muscle tone

A

PROM

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7
Q

Normal resting muscle tone is provided by

A

titin and weak actin myosin bonds and low level tonic activation from descending motor input

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8
Q

Loss of sarcomeres is a

A

structural adaptation to the shortened position so that the muscle generates optimal force at the new resting length

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9
Q

If a mm is immobilized in a lengthened position it will

A

add new sarcomeres

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10
Q

Cocontraction refers to

A

simultaneous contraction of antagonist muscles

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11
Q

LMNs are the only neurons that convey signals to

A

extrafusal and intrafusal skeletal muscle fibers

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12
Q

Two types of LMNs

A

alpha and gamma

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13
Q

AMNs are MNs with

A

large cells bodies and large myelinated axons that reside in brainstem and spinal cord

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14
Q

Gamma motor neurons consists of

A

medium sized myelinated axons

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15
Q

Axons of AMNs project to

A

extrafusal skeletal muscle, branching into numerous terminals as they approach mm

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16
Q

Axons of GMNs project to

A

intrafusal fibers in the muscle spindle

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17
Q

H reflexes are

A

monosynaptic reflexes elicited by electrically stimulating a nerve

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18
Q

Purpose of H reflexes

A

quantify the level of alpha motor neuron facilitation of inhibition

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19
Q

Medial UMN tracts (4)

A

Reticulospinal
Medial vestibulospinal tracts
Lateral vestibulospinal tract
Medial corticospinal tract

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20
Q

Reticulospinal tract

A

Facilitates bilateral LMN innervating postural and gross limb movement of mm throughout the body

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21
Q

Medial vestibulospinal tracts

A

receives info about head mvmnt and position from vestibular apparatus

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22
Q

Lateral vestibulospinal tract

A

responds to gravity information from vestibular apparatus

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23
Q

Medial corticospinal tract

A

Has direct connection from cerebral cortex to the spinal cord

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24
Q

Fractionation is

A

the ability to activate individual muscles independently of other mm (mvmnt of hands)

25
Q

Which is the most important pathway controlling goal-directed, voluntary movements

A

lateral corticospinal tract

26
Q

Origin of corticospinal tracts

A

primary motor, premotor, and supplementary motor cortex

27
Q

Signs of MN lesions

A 
paresis, paralysis 
muscle atrophy
involuntary mm contractions
abnormal mm tone
abnormal reflexes
disturbances of mvmnt efficiency and speed
impaired postural control
28
Q

Paresis is the

A

partial loss of voluntary contraction

29
Q

Muscle atrophy

A

loss of muscle bulk

30
Q

Most severe atrophy is produced by

A

denervation of skeletal muscle

31
Q

Flaccidity is the

A

lack of resistance to passive stretch

32
Q

Disorders of LMNs

A

Trauma, infection, degenerative or vascular disorders, and tumors can LMNs

33
Q

If LMN cell bodies and/or axons are destroyed then the affected muscles can undergo

A

loss of reflexes
atrophy
flaccid paralysis
fibrillations

34
Q

UMN lesions can produce several changes in mvmnt control including

A

paresis or paralysis
loss of fractionation of mvmnt
abnormal reflexes
velocity dependent hypertonia

35
Q

Paresis occurs in ___ lesions as a result of ___

A

UMN

inadequate facillitation of LMNs

36
Q

3 most common abnormal reflexes in those with chronic SCIs are

A

muscle stretch hyperreflexia
clonus
clasp-knife response

37
Q

Excessive mm contraction occurs when

A

spindles are stretched as a result of excessive firing of LMNs

38
Q

Clonus is

A

involuntary, repeating, and rhythmic muscle contractions

39
Q

Clasp-knife response occurs when

A

a paretic muscle is slowly and passively stretched and resistance drops at a specific point in the ROM

40
Q

____ __ ____ elicit the clasp knife response

A

type II afferents

41
Q

velocity dependent hypertonia limits

A

joint ROM, interferes with function, and may cause deformity

42
Q

myoplasticity is

A

adaptive changes within a muscle in response to changes in neuromuscular activity level and to prolonged positioning

43
Q

Spasticity is

A

neuromuscular overactivity secondary to UMN lesion

44
Q

What is the primary cause of stroke spasticity

A

brainstem UMN overactivity

45
Q

Measuring hypertonia

A

EMG

Ashworth scale

46
Q

Spastic cerebral palsy

A

abnormal supraspinal influences, failure of normal neuronal selection, and consequent aberrant muscle development lead to movement dysfunction

47
Q

Complete spinal cord injury

A

all descending neuronal control is lost below the level of the lesion

48
Q

Incomplete spinal cord injury

A

function of some ascending and/or descending fibers is preserved within the spinal cord

49
Q

Primary impairment with spastic cerebral palsy

A

paresis of agonist postural muscles

50
Q

Continuous prolonged immobilization of skeletal mm results in

A

contracture from loss of sarcomeres

51
Q

purpose of alpha gamma coactivation

A

maintain mm spindle sensitivity when extrafusal mm fibers contract

52
Q

Phasic stretch reflex AKA

A

myotatic reflex
muscle stretch reflex
deep tendon reflex

53
Q

reciprocal inhibition produces inhibition of the alpha motor neuron to what

A

antagonist muscle

54
Q

What contributes to spinal control of walking

A

afferent inpur
interneuorns
reciprocal signals crossing dorsal columb

55
Q

if LMN to mm is destroyed what sign

A

loss of reflexes and atrophy

56
Q

abnormal cutaneous reflexes that occur after an UMN lesion include what

A

Babinski

muscle spasm

57
Q

What limits movement in those who had stroke

A

paresis (dec agonist)
cant fractionate
abnormal timing of mm activation

58
Q

Clonus is characterized by what

A

involuntary, repetitive, and rhythmic mm contractions in response to mm stretch

59
Q

Decorticate rigidity occurs with what

A

lesions of superior midbrain

Semester 5 FSNM Exam 1 (6 decks)

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