Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroscience > Lecture 11: Posture and Balance > Flashcards

Lecture 11: Posture and Balance Flashcards

1
Q

what is Centre of mass (CoM)

A

point where the mass of the body is equally distributed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is Base of support (BoS)

A

area of the body in contact with the support surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is Centre of pressure (CoP)

A

Center of distribution of force applied to the supporting surface

Moves continuously around the CoM to keep it within the BoS (hearding dog)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is postural control

A

umbrella term

Controlling body position for orientation and stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is postural orientation

A

ability to maintain an appropriate position

(lean forward when walking up hill)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is postural stability/balance

A

Ability to control centre of mass (COM) relative to gravity and base of support (BOS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the stability if a person is sitting reading a book

A

large base of support

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the stability of a person standing to read

A

more demands than sitting because base of support is smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the stability of a person walking and looking forward

A

centre of mass does not stay within base of support, so there is a continuous state of imbalance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

do postural control requirements change wit the task and environment

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 main sources of sensory input to the CNS

A

somatosensory (70%)

vestibular system (20%)

Vision (10%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when learning a new skill, do we rely more on somatosensory input or vision for postural stability

A

vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 2 parts of Vestibular Apparatus

A

bony labyrinth

membranous labyrinth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the membranous labyrinth

A

Suspended within bony labyrinth

Filled with fluid (endolymph)

Sensory receptors (hair cells) that tell us where our head has moved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the Semicircular Canals

A

3 perpendicular bones in each ear

has cupula (gelatinous mass) with hair bundles inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what displaces hair cells in ear

A

Angular acceleration which
depolarizes all hair cells together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the purpose of the semicircular canals

A

stabilize vision during head turns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the names of the 3 Semicircular Canals and how are they positioned

A

anterior(superior), posterior, and horizontal canals

Oriented at 90 degrees to one another

anterior and posterior canals are 45 degrees from midline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the counter balanced design

A

Each canal works with a partner on the opposite side

Canals activate more strongly in response to movement in a particular plane

We increase activity in the semicircular canal on the side we are moving toward and decrease activity the side we are moving away from

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what movement are the horizontal canals sensitive to

A

Rotation in the transverse plane (head turns)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what 2 movements are the Superior/anterior and posterior canals sensitive to

A

Movement in sagittal plane (nodding)

Movement in the coronal plane (side-bending)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

in general, the direction of head movement corresponds to what in canals

A

an increase in the activity of that canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how are semicircular canals sensitive to angular acceleration

A

Frequency of action potentials increases with higher acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the 2 types of otolith organs

A

Saccule and Utricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are otolith organs

A

One utricle and saccule on each side that mirror the other side

Each contain a sensory epithelium (macula)

topped by crystals (otoconia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what type of movement are otolith organs sensitive to

A

linear movements and static head tilts

27
Q

what is the orientation of the utricle and what is it responsive to

A

more horizontal

responsive to horizontal movement (side bending, lateral displacement)

28
Q

what is the orientation of the Saccule and what is it responsive to

A

more vertical

responsive to vertical movement (up/down, forward/backward)

29
Q

how are hair cells in otoliths orientated and what movement are they sensitive to

A

Hair cells oriented in different directions

On opposite sides of each macula, hair cells are sensitive to opposite motions (half depolarizes)

30
Q

are otoliths sensitive to acceleration?

A

no. they have Tonic or sustained pattern of activation

31
Q

what 2 things are special about vestibular inputs

A

They are multisensory (receive visual and vestibular input)

vestibular nuclei provide very fast compensatory eye and head movements

32
Q

why is it important that the vestibular pathways are multi sensory

A
  • Essential for postural control and control of eye movements
33
Q

what is the Medial longitudina lfasciculus (MLF)

A

connection between vestibular and visual systems

tells the eyes which way they should move

Involved in the vestibular- ocular reflex (VOR)

34
Q

what is the vestibular- ocular reflex (VOR)

A

as head turns to the right while looking at something,

Right horizontal semicircular canal is active; left horizontal semicircular canal is inhibited

Eye musculature responsible for moving eyes to left are activated

Eye musculature responsible for moving eyes to the right are inhibited

35
Q

what is the function of the Involved in the vestibular- ocular reflex (VOR)

A

Keep eyes on target while head is moving

36
Q

what are Vestibulospinal Tracts

A

Involved in the control of postural orientation and stability

Vestibular nuclei give rise to the lateral and medial vestibulospinal tracts

37
Q

what is the Medial Vestibulospinal Tract

A

Arises from medial vestibular nucleus

Descends bilaterally in spinal cord

Regulates head/neck position

38
Q

which reflex is the medial vestibulospinal tract involved with

A

Vestibular cervical reflex

Moves head in opposite direction of motion

when falling forward, neck extends to protect neck

39
Q

what is the Lateral Vestibulospinal Tract

A

Arises from lateral vestibular nuclei

Controls proximal extensor muscle tone for maintenance of posture in legs

40
Q

what reflex is involved with the Lateral Vestibulospinal Tract

A

Vestibular spinal reflex (VSR)

Body flexes in opposite direction of motion

if our body is pushed to the right, we lean to the left to come upright

41
Q

what does the cerebellum do

A

Cerebellum provides input to medial and lateral vestibular nuclei

42
Q

what 2 things does the cerebellum distinguish between

A

Motions detected by otoliths and semicircular canals

Active vs passive movements

43
Q

what is the Vestibular Cortical System

A

vestibular information ascends bilaterally to the thalamus, then to the parietal cortex and insula

generates a head-in-space picture

44
Q

are vestibular and visual systems are matched to one another

A

yes

45
Q

what is Physiological vertigo

A

conflict between sensory systems (motion sickness)

46
Q

what is pathological vertigo

A

caused by a sudden imbalance of vestibular signals

47
Q

what is Spontaneous Nystagmus

A

movement of the eyes without stimulus.

48
Q

what is Benign Paroxysmal Positional Vertigo (BPPV)

A

Most common cause of vertigo

Displacement of otoconia from the otoliths into the posterior semicircular canal

Signals to the brain that movement is occurring despite no movement

49
Q

what is the Epley Maneuver

A

Treatment of posterior canal BPPV

Displaces the otoconia back into the otoliths using gravity

50
Q

what is the feedforward mechanism

A

anticipatory postural adjustments in anticipation of postural instability

51
Q

what is the feedback mechanism

A

corrective postural control strategies in response to unanticipated postural instability

52
Q

what are the 3 types of balance control

A

Static/Steady State balance

Anticipatory/Proactive balance

Reactive balance

53
Q

what is Static/Steady State balance

A

Ability to control the COM relative to the BOS in predictable and unchanging conditions

(standing on leg, keeping self balanced)

54
Q

what is Anticipatory/Proactive balance

A

Ability to activate muscles for balance in advance of potentially destabilizing voluntary movements (ie. picking up a box)

  • Using feedforward mechanisms
55
Q

what is Reactive balance

A

Ability to recover a stable position following an unexpected perturbation

  • Using feedback mechanisms

(bus hits the breaks and we need to rebalance)

56
Q

why is Static and dynamic balance really a continuum

A

when we are “static” we still sway so we are still moving

57
Q

what are the 2 postural stability functions

A

anticipatory (minimize upcoming issues - feedforward)

reactive (correct errors - feedback)

58
Q

what is Anticipatory Postural Adjustment

A

Activation of postural muscles before execution of voluntary goal

59
Q

why is Reticulospinal Tract important for postural control

A

Bilateral terminations

Postural control to support skilled/coordinated movements

Muscle tone

60
Q

what is ankle strategy

A

Activated during small perturbations and firm surfaces

Rely heavily on somatosensory input

Distal muscles activated first

61
Q

what is the hip strategy

A

(standing on balance beam)

Activated during larger or faster perturbations

Rely more on vestibular and visual inputs

Proximal muscles activated first

62
Q

what is change in support strategies

A

Moving the limbs to change the BOS

Humans can adapt by shifting from one strategy to another

reaching or stepping

63
Q

what does abnormal postural control look like

A

Increased sway

slower anticipatory control

Increased reliance on hip and stepping strategies

64
Q

how does cognition contribute to abnormal postural control in people with strokes

A

Reaction times increase with increasing postural control demands

Neuroscience (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions