Balance And Equilibrium

Question 1

Vestibular system

Answer 1

Membranous fluid filled chambers located deep in temporal bone within the ear

Question 2

4 functions of the vestibular system

Answer 2

Balance and equilibrium
Detect head motion
Determine gravitational vertical
Fixation of eyes while head is moving

Question 3

Sensory organs of the vestibular system

Answer 3

3 semicircular canal -

2 otolithic organs - *****

Question 4

CN 8

Answer 4

Vestibular nerve

Question 5

Sensory receptors of the vestibular system (hair cells) innervated by?
What kind of neurons?
Cell body location

Answer 5

Innervated by CN8
Bipolar sensory neurons
Scarpa’s ganglion

Question 6

Stereocilia

Answer 6

Hair cells

Question 7

Information regarding alignment of hair cells

Answer 7

Conveyed to brainstem and cerebellum via CN8, then to motor neurons of extraocular muscles (brainstem) and antigravity muscle (spinal cord)

Question 8

Vestibular hair cells

Answer 8

Specialized mechanoreceptors sensitive to bending or distortion (physical stim)

Question 9

2 components of a vestibular hair cell

Answer 9

20-30 Stereocilia and a single large cilium called kinocilia

Question 10

Orientation of kinocilia and stereocilia

Answer 10

Crewcut***

Morphological axis of polarity - they go slanted in the middle

Question 11

Directional alignment of kinocilia dictates

Answer 11

AP firing patterns

Question 12

6 degrees of freedom

Answer 12

Yaw - rotation around z axis
Roll - x
Pitch - y

Question 13

Translational direction

Answer 13

Linear xyz

Question 14

Semicircular canals anatomy - 4

Answer 14

Both ends of each canal terminate on the utricle - one end swells before joining (ampula) which houses the sensory epithelium (crista) which contains hair cells. These hair cells extend into the cupula

Question 15

Number of hair cells/ semicircular canal

Answer 15

7000

Question 16

Hair cells project into

Answer 16

Gelatinous cupula

Question 17

Cupula bends in response to

Answer 17

Movement of endolymph fluid - pushes the cupula but wont get passed it (?)

Question 18

Direction of endolymph flow is ___ direction of head turn

Answer 18

Opposite to

Question 19

Clockwise flow of the fluid will?

Answer 19

Depolarize the left and hyperpolarize the right

Question 20

Firing frequency at rest

Answer 20

Tonic level