functional neuroanatomy of balance W3

Question 1

what bodily systems are involved in balance

Answer 1

MSK system
neurological system
cardiovascular system

Question 2

what are stretch reflexes

Answer 2

muscle contraction in response to stretching,, in order to maintain constant muscle length

Question 3

benefits of spinal reflexes?

Answer 3

short distances
therefore fast response

Question 4

inputs for balance?

Answer 4

eyes
inter-ear balance organs
muscles, joints, tendons, skin

Question 5

what areas of the brain are involved in balance

Answer 5

cerebellum, brainstem

Question 6

2 types of ‘outputs’ in balance pathway?

Answer 6

reactive postural response
anticipatory postural adjustments

Question 7

vestibular system - where are structures of the inner ear located?

Answer 7

in the labyrinth - series of interconnected fluid-filled cavities inside the petrous temporal bone

Question 8

structures in the inner ear?

Answer 8

vestibule
semicircular canals (balance)
cochlea (hearing)

Question 9

what is the vestibule?

Answer 9

oval structure at centre of labyrinth. formed by utricle and saccule

Question 10

function of the vestibule?

Answer 10

detect linear acceleration - head position with respect to gravity

Question 11

what are the semicircular canals?

Answer 11

3 loops - anterior posterior and lateral
positioned at right angled from eachother

Question 12

function of semicircular canals?

Answer 12

detect angular (rotational) acceleration

Question 13

what cells in the vestibular system detect movement of the fluid in the labyrinth

Answer 13

mechanosensitive hair cells

Question 14

structure of mechanosensitive hair cells?

Answer 14

apical surface covered by cilia
cells covered by otolithic membrane

Question 15

what is the otolithic membrane

Answer 15

jelly like structure containing many small crystals called otoliths

Question 16

what does movement cause in mechanosensitive hair cells

Answer 16

otolithic membrane lags behind layer of hair cells, hair cells convert this kinetic energy into nervous impulses

Question 17

3 categories of ‘dizziness’

Answer 17

syncope/presyncope
vertigo
altered balance

Question 18

syncope/presyncope cause?

Answer 18

cardiovascular

Question 19

vertigo cause?

Answer 19

vestibular disorders

Question 20

what is vertigo associated with?

Answer 20

nausea, vomiting, nystagmus

Question 21

nystagmus meaning

Answer 21

abnormal movements of the eyes

Question 22

what is altered balance caused by?

Answer 22

disruption to balance pathways:
-input?
-processing?
-output?

Question 23

vertigo definition?

Answer 23

abnormal perception of movement due to conflicting visual, proprioceptive and vestibular information about position in space

Question 24

most common cause of vertigo?

Answer 24

benign paroxysmal positional vertigo (BPPV)

Question 25

pathophysiology of BPPV?

Answer 25

otolithic debris affecting free flow of endolymph in semicircular canals.

Question 26

name of fluid in semicircular canals?

Answer 26

endolymph

Question 27

causes of BPPV?

Answer 27

spontaneous. may follow after minor head injury

Question 28

BPPV features?

Answer 28

transient (seconds)
often precipitated by movement
self limiting

Question 29

how is BPPV diagnosed?

Answer 29

Dix-Hallpike manoeuvre - patient lowered backwards, head at 20degrees over back of couch. nystagmus may be seen after 20/30 seconds, sometimes up to a minute.

Question 30

BPPV treatment?

Answer 30

Epley manoeuvre helps move debris to utricle and saccule

Question 31

features of Meniere disease?

Answer 31

vertigo
tinnitus
feeling of fullness in ear
attacks last a few hours
can progress into deafness

Question 32

management of Meniere disease?

Answer 32

low salt diet
vestibular sedative medications
surgery to increase endolymphatic drainage