Motor Control 4 Flashcards Preview

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Flashcards in Motor Control 4 Deck (28)
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1
Q

What does the Vestibular system do?

A

Process sensory information related to head position, spatial orientation (with respect to gravity) and movement

2
Q

What is the vestibular bony ‘labyrinth?

A

Part of the vestibular system responsible for balance and the position of the body in space

3
Q

Where is the bony labyrinth found?

A

In the temporal bone

4
Q

What is perilymph?

A

The substance that separates the membranous labyrinth from the bony labyrinth

5
Q

What is endolymph?

A

The liquid inside the bony labyrinth

6
Q

What is the structure of the labyrinth in the inner ear?

A

3 semicircular canals (anterior, posterior, lateral), positioned in line with each plane of movement

7
Q

What plane is the anterior semi-circular canal in?

A

Frontal plane

8
Q

What plane is the posterior semi-circular canal in?

A

Saggital Plane

9
Q

What plane is the lateral semi-circular canal in?

A

Transverse Plane

10
Q

What is the name of the enlarged section of each semicircular canal where it connects with the Utricle?

A

Ampullae

11
Q

What is located within the Ampullae?

A

The Crista Ampullaris

12
Q

What does the cupula around the crista ampullaris do?

A

It deforms due to angular acceleration of the head which stimulates hair cells in the crista ampullaris which sends signals to the brain to detect angular head motion

13
Q

What is the crista ampullaris?

A

A cone shaped structure in the ampullae covered in hair cells that detect angular acceleration

14
Q

What are the 5 sensory organs of the Labyrinth?

A

3 Semicircular canals

2 Otolith Organs (Utricle and Saccule)

15
Q

What is kinocilium and stereocilia?

A

Kinocilium: Longer hairs on the hair cell
Stereocilia: The shorter hairs of the hair cells

16
Q

What occurs if the kinocilium deflects towards the stereocilia?

A

Decrease of firing rate/hyperpolarisation

17
Q

What occurs if stereocilia deflect towards the kinocilium

A

Increase in firing rate/depolarisation

18
Q

If you angularly accelerate in one direction, what direction will the endolymph move in as you accelerate?

A

the other direction

19
Q

If you angularly accelerate in one direction, what direction will the endolymph move in once you start to decelerate?

A

The same direction as you moved

20
Q

How does activity of one semicircular canal affect the other?

A

It inhibits the opposite side

21
Q

If the head accelerates in a counterclockwise direction, explain what will happen in the semicircular canals of both sides of the head

A

Endolymph will travel clockwise, which will cause depolarisation/increased firing rate of the left side, and hyperpolarisation/decreased firing rate on right side. Both will send excitatory signals to their own side and inhibitory signals to the opposite side, but as the right side is decreased firing rate, it does not inhibit the left side much, but the left side does inhibitthe right side a lot

22
Q

What is the macula?

A

A patch of the epithelium of the utricle and saccule that has hair cells on it

23
Q

How are the hair cells orientated on the macula?

A

They are not all in the same direction.

24
Q

What can (the hair cells on) the macula detect?

A

Head tilt and linear acceleration, and position with respect to gravity

25
Q

Where are the saccule and utricle found?

A

In the vestibule

26
Q

how do the hair cells on the macula of the utricle/saccule detect head tilt?

A

Otolith crystals that sit on top of them will be affected by gravity when the body accelerates linearly or tilts, shifting the hair cells and affecting the firing rate

27
Q

What is relationship between strength and length of stimulus, and the response?

A

Stronger stimulus leads to stronger response with shorter latency
Longer stimulus means longer response

28
Q

What are the two ways higher levels of the brain can modulate reflex mechanisms?

A
Reflex suppression (raises threshold for reflex excitation)
Reflex Potentiation (lowers the threshold for reflex excitation)