Auditory and Vestibular system (CN VIII) Flashcards Preview

Anatomy > Auditory and Vestibular system (CN VIII) > Flashcards

Flashcards in Auditory and Vestibular system (CN VIII) Deck (61):
1

CN VIII has 2 divisions, what are they

cochlear - sound
vestibular - head position and movement

2

what is the name of the mechanoreceptor cells of the auditory and vestibular system

hair cells

3

the auditory and vestibular systems are both embedded w/in what bone

temporal bone

4

The bony labyrinth is composed of what ?

-cochlea (coiled thing)
-vestibule
-3 semicircular canals

5

the membranous labyrinth is composed of ?

-cochlear duct
-utricle (connected to semicircular ducts)
-saccule (connected to cochlea and utricle)
-3 semicircular ducts

6

what is the fluid that fills the bony labyrinth and what is it similar to

perilymph, similar to CSF

7

what is the fluid that fills the membranous labyrinth what is it similar too

endolymph, similar to intracellular fluid

8

what seperated the perilymph from the endolymph, AND why are they significant

tight junctions - create membrane potentials from the difference in ion conc.

9

hair cell microvilli are known as ______

stereocilia

10

what is the name given to the tallest stereocilia

kinocilium

11

what region of the auditory and vestibular systems has hair cells that lack kinocillia

cochlea

12

what is the cause of Meniere's disease

obstruction of flow resulting in swollen membranous labyrinth

13

the tips of the kinocillia are embedded into ?

gelatinous material

14

how are hair cell receptors transduced

movement in the gelatinous material causes deflection of the sterocillia = receptor potential transduced

15

deflection towards the tallest sterocillia causes

depolarization of the hair cell

16

deflection away from the tallest sterocillia causes

hyperpolarization of the hair cell

17

deflection perpendicular to the sterocillia causes

nothing, no effect

18

what is the role of the outer and middle ear

convey airborne sound vibrations to fluid filled inner ear

19

what are the 2 muscles of the middle ear and what is their main function

-stapedius - pull stapes away from oval window = stiffening
-tensor tympani - pulls malleus toward middle ear = stiffeneing
****** Both work to stiffen ossicular chain******

20

the _____ m. blocks the sounds of your own voice, whereas the _____ m. blocks chewing sounds

stapedius
tensor tympani

21

what middle ear muscles innervated by

-stapedius - CN VII
-tensor tympani - CN V

22

What are the 3 components of the structure of the Cochlea, and what type of lymph resides within each

1 - scala vestibula - perilymphatic space
2 - scala media - endolymph
3 - scala tympani - perilymphatic space

23

where does the scala tympani end ?

Ends blindly at the round window

24

where is the organ of corti in the ear

rests on basilar membrane of the cochlea, w/in the stri media

25

what is the spongy bone w/in the cochlea called

modiolus

26

what are the 2 groups of cells found in the organ of corti

-inner hair cells - unattached to tectorial membrane
-outer hair cells - attached to tectorial membrane

27

what is the difference b/w the inner and outer hair cells of the organ of corti on how they become stimulated

-inner (unnattached) stimulated by endolymph movement across sterocilli
-outer (attached) stimulated by vibrations in basilar membrane

28

movement of ______ causes a pressure pulse in the scala vestibuli of the organ of corti, which leads to a traveling wave of deformations in the ________

stapes at the oval window, basilar membrane

29

Explain "mechanical tuning"

the tonotopic organization of the auditory system based upon the amplitude and frequencies of waves on the basilar membrane

30

cochlear implants are based upon the tonotopic org. of the auditory system. With that said we place a coil of electrodes where to stimulate the intact CN VIII nerve endings

round window into the scala tympani at different points along the basilar membrane

31

CNS auditory processing analyzes what ?

sound frequency and intensity

32

what is the primary ascending pathway in CNS auditory processing

lateral lemniscus pathway

33

the lateral lemniscus pathway has fibers that will first synapse at the ____________ nucleus, then at the ______, then project to the inferior brachium and ending at the _________ nucleus

-superior olivary nucleus -----> inferior colliculus
-------> medial geniculate nucleus of the thalamus

34

where is the primary auditory cortex anatomically on the brain

transverse temporal gyri
***distinguish bc gyri run mediolaterally vs. front to back***

35

T/F Sound that reaches the left ear before the right will be heard softer and less intense

F , will be heard louder and more intense

36

IN CNS auditory processing what it the nucleus important in sound localization

superior olivary nucleus

37

T/F the lateral lemniscus pathway carries information from both ears ?

True

38

what is an audiogram

way to meausre someones threshold for hearing via
-headphones (air conduction)
-vibration (bone conduction)

39

what is the difference b/w a conductive hearing loss and a sensorineural hearing loss

conductive is when sound cant reach labyrinth
sensorineural is when there is damage to hair cells or cochlea nuclei

40

in an audiogram, air conduction (headphones) needs and intact _____________ ?

outer, middle, and inner ear

41

a defect in bone conduction is usually the result of ?

sensorineural problem

42

the most common air conduction defect is the result from

middle ear infection

43

what detects angular acceleration of the head

semicircular ducts

44

one end of each semicircular duct closest to the utricle is called the

ampulla (which contains the crista)

45

sterocillia hair cells in the semicircular ducts are arranged in a transverse called the _________ and extend into a gelatinous mass above called the ____________

crista
cupula

46

deflection of the cupula leads to increase afferent firing in the semicircular ducts. During deflection as rotation begins, what is laggin behind which deflects the cupula and inevitably stimulates the sterocilla hair cells

endolymph lags behind during rotation

47

if rotation in the semicircular duct continues what happes

endolymph catches up and no deflection of the cupula occurs

48

what detects linear acceleration in the vestibular system

utricule and saccule

49

what is the difference in the arangement of macula and sterocillia in the utricle and saccule?

utricle - macula horizontal and sterocilla face up
saccule - macula vertical and sterocilla face laterally

50

what is the otolithic membrane and where is it found

a dense gelatinous material of the macula in the utricle and saccule (more dense than endolymph)

51

what is the difference b/w the utricle and the saccule with regards to what direction of linear acceleration they can detect

utricle - forward/backward and side to side
saccule - forward/backward and up/down

52

what is the primary afferent cell body in the internal auditory canal that has vestibular projections

Vestibular ganglion (Scarpa's ganglion)

53

The Vestibular nuclei has output to where ?

spinal cord
VPL of thalamus to cortex
braintstem

54

vestibulospinal fibers that have excitatory projections to antigravity muscles follow what tract ?

lateral vestibulospinal tract

55

vestibulospinal fibers that stabalize head movements as we walk and coordinate head/eye movements travel on what tract ?

medial vestibulospinal tract

56

the vestibular system works to prevent images from moving on the retina (keep images on the retina), this is known as _____________

Vestibuloocular reflex (VOR)

57

what is the afferent and efferent limb of the vestibuoocular reflex

afferent - CN VIII
efferent - CN III, IV, VI

58

what is nystagmus

rapid eye movements in the opposite direction bc the VOR cant compensate for head movements

59

alcohol has the ability to alter the density of the ______ and ______ making semicircular ducts sensitive to gravity

cupula and endolymph (the spins when your drunk)

60

what is Rombergs sign

when patient closes eyes and loses balance

61

the posstion sense is mediated by what 3 systems working together

1 - vestibular
2 - proprioceptive
3 - visual