Brainscape's Knowledge GenomeTM

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


See full index

Yr2 Control - Term 2 and 3 > Posture and Balance > Flashcards

Posture and Balance Flashcards

1
Q

What systems contribute to posture and balance? (3)

A
  • Vestibular system
  • Visual system
  • Somatosensory system (proprioception)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the structural features of the vestibular system involved in posture and balance? (2)

A
  • Semicircular canals (x3)

- Vestibule (contains utricle and saccule)

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

What nerve is involved with balance in the vestibular system?

A

Vestibular branch of the vestibulocochlear nerve (VIII).

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

What nerves is the vestibular branch composed of? (3)

A
  • Utricular nerve
  • Saccular nerve
  • Ampullary nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many degrees of freedom are there in vestibular navigation?

A

6 degrees of freedom.

-3 translational, 3 rotational

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

What are the translation degrees of freedom? (3)

A

X, y and z.

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

What is translational motion and linear acceleration detected by?

A

Utricle and saccule.

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

What are the rotational degrees of freedom? (3)

A
  • Roll (around x)
  • Pitch (around y)
  • Yaw (around z)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is rotational motion and angular acceleration detected by?

A

Semicircular canals.

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

What are the main sensory detectors of the utricle and saccule?

A

Maculae.

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

What does the macula contain?

A

Matrix of cells surrounding hair cells innervated by utricular and saccular nerves.

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

What structures do the hair cells contain that provide information about movement?

A
  • Multiple cilia

- 1 kinocilium

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

What do the cilia penetrate into?

A

The otolithic membrane.

-gelatinous calcium carbonate crystals

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

What is the effect of bending of the cilia and kinocilium?

A

Bending of cilia towards kinocilium&raquo_space; increased firing in nerve&raquo_space; DEPOLARISATION.
Bending of cilia away from kinocilium&raquo_space; decreased firing in nerve&raquo_space; HYPERPOLARISATION.

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

What sort of ion channels do hair cells contain?

A

K+ channels.

-mechanoreceptors

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

What happens when the K+ channels are distorted?

A

K+ channels become activated
» activation of VG Ca channels
» glutamate release.

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

What is the macula activated by?

A

Head tilting.

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

What does the macula provide information about? (2)

A
  • Static equilibrium

- Dynamic equilibrium

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

What is static equilibrium?

A

Position of head relative to horizontal.

-sensitivity

20
Q

What is dynamic equilibrium?

A

Linear acceleration / deceleration.

21
Q

What planes are the maculae orientated in?

A

UTRICLE – horizontal.
SACCULE – vertical.

Opposing directions&raquo_space; better sensitivity.

22
Q

What are the utricle and saccule also known as collectively?

A

Otolith organs.

23
Q

What do the otolith organs provide information about? (3)

A
  • Head tilting
  • Gravity
  • Linear acceleration
24
Q

What are the main functional features of the semicircular canals?

A
  • Main sensory structure is localised to AMPULLA

- Canal on both sides of head work in pairs

25
Q

What do the semicircular canals provide information about? (2)

A
  • Rotational movements

- Angular acceleration

26
Q

What are the semicircular canals filled with?

A

Endolymph.

27
Q

What is an ampulla?

A

Bulge at base of semicircular canal.

-location of main sensory structures

28
Q

What is a cupula?

A

Gelatinous membrane in ampulla containing sensory processes.

  • hair cells and cilia
  • forms barrier against endolymph flow
29
Q

What nerve innervate hair cells in the semicircular canals?

A

Ampullary nerve.

-from CNVIII

30
Q

How does head rotation lead to nerve impulses?

A 
Head rotation
>> endolymph inertia (lags behind)
>> cupula bends in opposite direction to rotation
>> distortion of cilia
>> excites / inhibits sensory nerves.
31
Q

Why are the semicircular canals arranged in pairs?

A

Allows for comparison (pull-push mechanism).

  • 1 side depolarised, 1 side hyperpolarised
  • greater sensitivity
32
Q

What nerve do sensory afferents of the vestibular pathways run in?

A

Vestibulocochlear nerve (CNVIII).

33
Q

Where do sensory afferents from the otolith organs (utricle and saccule) project to?

A

Lateral nucleus.

34
Q

Where do the efferents from the otolith organs (utricle and saccule) project to?

A

From lateral nucleus&raquo_space; cerebellum and limb motor neurons.

-maintain upright body posture

35
Q

Where do sensory afferents from the semicircular canals project to?

A

Medial nucleus.

36
Q

Where do the efferents from the semicircular canals project to?

A

From medial nucleus&raquo_space; neck motor neurons and extraocular nerves (III, IV, VI).
-orientate head and stabilise retinal image

37
Q

What is a major function of the vestibular system?

A

To maintain forward vision during head movements.

38
Q

What enables you to maintain forward vision during head movements?

A

Vestibulo-ocular reflex (VOR).

-involves semicircular canals and extraocular muscles

39
Q

What is nystagmus?

A

Rapid involuntary eye movements.

  • travel slowly in one direction then rapidly flick in opposite direction
  • e.g. when spinning
40
Q

What is rightwards nystagmus?

A

Eyes track slowly to the left then rapidly flick to the right.

41
Q

What is caloric testing?

A

Lie patient down and irrigate ear with warm / cold water&raquo_space; convection currents in endolymph.

  • WARM&raquo_space; increased firing
  • COLD&raquo_space; decreased firing
42
Q

What diseases affect the vestibular system? (5)

A
  • Meniere’s syndrome
  • Benign paroxysmal positional vertigo
  • Ototoxicity
  • Vestibular neuritis / brainstem carcinoma / infarction / haemorrhage
  • Medulloblastoma
43
Q

What is Meniere’s syndrome?

A

Increased endolymph volume and membranous labyrinth rupture.

|&raquo_space; earache, tinnitus, dizziness, falls

44
Q

What is benign paroxysmal positional vertigo?

A

Calcium carbonate crystals dislodged from otoliths.

-movement in canal&raquo_space; illusion of movement and dizziness

45
Q

What is ototoxicity?

A

Damage due to drugs / chemicals.

|&raquo_space; damage of vestibulocochlear nerve

46
Q

What is medulloblastoma?

A

Childhood tumour growth in cerebellum.
-unable to use lateral vestibular information from otoliths
» postural instability

47
Q

What do vestibular neuritis / brainstem carcinoma / infarction / haemorrhage lead to?

A

Disrupted postural control secondary to vestibular system damage.

Yr2 Control - Term 2 and 3 (17 decks)

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