Motor System Flashcards

1
Q

Two main muscle systems in the body

A
  1. axial or proximal

2. distal

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2
Q

axial or proximal muscles mediate

A

posture and balance movements

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3
Q

distal muscles mediate

A

limb movements and fine movements of digits, throat and tongue

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4
Q

motor neurons innervating PROXIMAL muscles are located

A

MEDIALLY in the ventral horn

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5
Q

motor neurons innervating DISTAL muscles are located

A

LATERALLY in the ventral horn

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6
Q

Medial brainstem pathway is what %?

A

75%

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7
Q

medial - vestibulospinal tracts originate in

A

the vestibular nuclei

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8
Q

medial - vestibulospinal tracts carry information for

A

reflex

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9
Q

medial - vestibulospinal tracts control

A

balance and posture

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10
Q

medial - reticulospinal tracts originate in

A

the reticular formation of the pons and medulla

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11
Q

medial - reticulospinal tracts descend

A

ipsilaterally

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12
Q

medial - reticulospinal tracts synapses in

A

the spinal cord on interneurons and motor neurons

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13
Q

medial - reticulospinal tracts they maintain

A

posture

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14
Q

medial - reticulospinal tracts they are controlled by

A

the motor cortex

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15
Q

medial - tectospinal tracts originate in the

A

superior colliculus of the midbrain

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16
Q

medial - tectospinal tracts descends

A

ipsilaterally and contralaterally

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17
Q

medial - tectospinal tracts goes down only to the

A

cervical level

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18
Q

medial - tectospinal tracts coordinates

A

head and eye movement

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19
Q

medial - tectospinal tracts is controlled by the

A

motor cortex

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20
Q

lateral brainstem pathway is what %?

A

25%

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21
Q

lateral - rubrospinal tract originates in the

A

magnocellular portion of the red nucleus in the midbrain

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22
Q

lateral - rubrospinal tract is controlled by the

A

motor cortex

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23
Q

aminergic pathways are involved with

A

reticular formation and are important for sleep

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24
Q

muscle sensory receptors and stretch reflexes -

A

LOWEST LEVEL of motor hierarchy

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25
Q

reflex definition

A

involuntary, relatively stereotyped motor response to a specific sensory stimulus

26
Q

location of a stimulus determines

A

what muscle is activated

27
Q

strength of stimulus determines

A

amplitude of motor response; response is graded

28
Q

spinal reflexes

A

reflex is where a stimulus arises from receptors in muscles, joints or skin and where the neural circuitry is responsible for the motor response and contained entirely in the spinal cord

29
Q

spinal reflexes are used by

A

higher brain centers to generate more complex behaviors and used in clinical diagnosis

30
Q

muscle sensory receptors

A

sensory receptors that detect features of skeletal muscle and their afferent input is used in spinal reflex circuits

31
Q

muscle spindel senses muscle

A

length and rate of change
it’s embeded in the muscle
two types: group Ia and group II

32
Q

golgi tendon organ senses muscle

A

tension during contraction
located at junction between muscle fibers and tendon
connected in a series with the muscle
sensory axons are group Ib

33
Q

where do axons of gamma motor neurons enter the spinal cord?

A

in the center of the spinal cord

34
Q

where to axons of gamma motor neurons terminate at?

A

the top and bottom polar regions of intrafusal fibers

35
Q

where do gamma motor neurons live?

A

ventral horn of spinal cord

36
Q

activation of gamma motor neurons innervating the spindle causes contraction of

A

both polar ends of intrafusal fibers

37
Q

control of posture

A

intermediate level of motor hierarchy

38
Q

posture is the overall

A

position of the body and limbs relative to one another and their orientation in space

39
Q

3 main functions of postural adjustments

A
  1. support the head and body against gravity
  2. maintaining the body’s center of mass over the base of support
  3. stabilize the supporting parts of the body while other parts move
40
Q

anticipatory (feedforward)

A

these predict or anticipate disturbance to posture and make adjustments BEFORE motor acts - can be refined with experience like balance on a bike

41
Q

postural set

A

the preparatory state where a specific postural response is selected in advance of the stimulus so that it is then execute automatically

42
Q

compensatory (feedback)

A

automatic adjustments produced in a reflex-like fashion when there is an actual loss of balance to the body
these responses are flexible

43
Q

postural adjustments are generated by

A

pre-existing organized motor patterns that are triggered by sensory experiences; can be enhanced or reduced by the highest level fo motor hierarchy

44
Q

voluntary movement

A

highest level of motor hierarchy

45
Q

voluntary movement entails 5 major phases: 1. goal elicitation

A

involves prefrontal cortex

Ex: i want to walk across the room

46
Q

voluntary movement entails 5 major phases: 2. target identification

A

occurs in the posterior parietal cortex, involves both visual and somatosensory cortex
what is it you want to act on?

47
Q

voluntary movement entails 5 major phases: 3. planning

A

occurs in secondary motor cortex, specifically the premotor cortex and supplementary motor cortex
this is not conscious planning - that occurs in the basal ganglia this is more like programming

48
Q

voluntary movement entails 5 major phases: 4. execution

A

mediated by the primary motor cortex

it sends out the commands

49
Q

voluntary movement entails 5 major phases: 5. feedback monitoring

A

occurs in the cerebellum

monitors commands coming out of cortex

50
Q

cerebellum is divided into 4 functional parts: 1. vestibulocerebellum

A

makes connections with the vestibular systme to control the medial motor systema nd vestibular reflexes
flocculondoular lobe

51
Q

cerebellum is divided into 4 functional parts: 2. spinocerebellum

A

controls axial and proximal muscles of the medial motor system - how the cerebellum is monitoring the entire body
vermis

52
Q

cerebellum is divided into 4 functional parts: 3. spinocerebellum - intermediate hemisphere

A

controls distal motor neurons of lateral motor system

53
Q

cerebellum is divided into 4 functional parts: 4. cerebrocerebellum

A

monitors the activity of the motor cerebral cortex and plays a role in initiation planning and timing of movements

54
Q

cerebellar cortex consits of 2 triads

A
  1. located in granular layer

2. located in molecular layer

55
Q

basal ganglia consists of 4 functial circuits: 1. motor circuit

A

motor planning and control (frontal lobe)

56
Q

basal ganglia consists of 4 functional circuits: 2. oculomotor circuit

A

control of saccade eye movements, eye movement used when looking at objects

57
Q

basal ganglia consists of 4 functial circuits: 3. dorsolateral prefrontal cortex cirucit

A

modulation of prefrontal executive cognitive functions

58
Q

basal ganglia consists of 4 functial circuits: 4. lateral orbiofrontal circuit

A

behavioral set, context, emotions and motivation

59
Q

the basal ganglia is like a what on the cerebral cortex??

A

a break!

60
Q

Direct Pathway of the basal ganglia

A

excites the cortex

61
Q

indirect pathway of the basal ganglia

A

inhibits the cortex