ENT Flashcards Preview

► Med - Anatomy & Physiology > ENT > Flashcards

Flashcards in ENT Deck (69)
Loading flashcards...
1
Q

what does the inner ear consist of?

A

a membranous labyrinth containing endolymph in a bony labyrinth containing perilymph

2
Q

what do both hearing and equilibrium use?

A

hair cells as sensory receptors

3
Q

what are hair cells

A

epithelial cells that function as mechanroceptors

4
Q

what do hair cells synapse with?

A

a sensory neuron

5
Q

what do hair cells have?

A

about 80 long stereocilia and a longer kinocilium

6
Q

where does hair cell’s kinocilium project?

A

into the endolymph

7
Q

what does the stereocilia contain?

A

mechanically regulated ion channels

8
Q

what does bending the stereocilia one direction do?

A

open ion channels that depolarize the hair cells

9
Q

what happens when ion channels that depolarize hair cells are open?

A

it causes more neurotransmitter release that increases the rate of action potentials in the sensory neuron

10
Q

what does bending the stereocilia in the other direction do?

A

closes the ion channels, hyperpolarizing the hair cells

11
Q

what happens when ion channels close, hyperpolarizing the hair cells

A

it causes less neurotransmitter release that reduces the rate of action potentials in the sensory neuron

12
Q

what does sound consist of?

A

pressure waves in the air

13
Q

what is the frequency (pitch)?

A

the number of waves per second

14
Q

what is the amplitude (loudness)?

A

the height of the pressure waves

15
Q

what dos the cochlear duct (scala tympani) separate?

A

the vestibular duct (scala vestibuli) and typanic duct (scala tympani)

16
Q

where does the vestibular duct begin?

A

at the oval window

17
Q

where does the tympanic duct end?

A

at the round window

18
Q

where are the tympanic and vestibular ducts connected?

A

at the end of the cochlea (helicotrema)

19
Q

where does the hearing organ (spiral organ) sit?

A

on the basilar membrane

20
Q

what does the basilar membrane separate?

A

the cochlear and tympanic ducts

21
Q

where do hair cells on the basilar membrane project?

A

up to the overlying tectorial membrane

22
Q

when the basilar membrane moves what is true of the sterocilia?

A

the hair cells are bent

23
Q

what are the inner row of hair cells used for?

A

hearing

24
Q

what are the outer row of hair cells used for?

A

to regulate the tension of the spiral ligament of the basilar membrane

25
Q

trace a soundwave (3) (VVC)

A

1) they vibrate the tympanic membrane
2) vibrates the auditory ossicles
3) creates pressure in the vestibular duct

26
Q

what does the pressure wave cause? (3) (RMB)

A

1) the round window to bulge out
2) moves the basilar membrane
3) bends the hair cell processes at one location

27
Q

after the pressure wave what does sound distort?

A

the basilar membrane at a specific location

28
Q

what does the location of the sound distortion at the basilar membrane at the specific location depend on?

A

on the frequency of sound and the width of the basilar membrane

29
Q

after sound distortion occurs, what does lower frequency sound distort?

A

the basilar membrane further from the oval window than higher frequencies

30
Q

what does the sound distortion form?

A

the basis of pitch discrimination

31
Q

what does higher amplitude sound stimulate?

A

more hair cells at a location

32
Q

what is Timbre?

A

the quality of sound

33
Q

why is timbre the quality of the sound?

A

since most sound areas are complex with several frequencies being produced and several areas of the spiral organ

34
Q

what do the two muscles attached to the auditory ossicles in the middle ear do?

A

dampen loud noises

35
Q

what is the feedback circuits from the superior olivary nucleus to the hair cells used for?

A

to filter out minor vibrations and noise

36
Q

where are the sensory neuron cell bodies located?

A

in the spiral ganglion near the center of the cochlea

37
Q

what do axons from the spiral ganglia form?

A

the cochlear branch of the vestibuloochlear nerve (VII)

38
Q

where do the axons that form the cochlear branch of the vestibuloochlear nerve synapse?

A

in the cochlear nuclei of the medulla

39
Q

what happens after the cochlear branch of the vestibuloochlear nerve synapses?

A

the axons then ascend to the inferior colliculi

40
Q

what do axons often ascend to the inferior colliculi through?

A

the superior olivary nucleus

41
Q

what does the inferior colliculi send?

A

auditory information to the superior colliculi

42
Q

what does the inferior colliculi send auditory information to the superior colliculi for?

A

reflexes and to the medial geniculate nuclei for relaying to the auditory cortex

43
Q

what detects linear acceleration, rotation and position of the head?

A

the vestibule and semicircular canals

44
Q

what detects linear acceleration and position of the head with respect to gravity:?

A

the static labyrinth (utricle and saccule)

45
Q

what are the receptors (maculae) in the static labyrinth?

A

epithelia containing hair cells

46
Q

where do the hair cell processes of the static labyrinth extend into?

A

a gelatinous otolith membrane

47
Q

what does the gelatinous otolith membrane contain?

A

dense calcium carbonate crystals (otoliths)

48
Q

when the head tilts or accelerates what happens to the otoliths?

A

they move gelatinous material bending the hair cell processes

49
Q

what happens after the otolights move the genlatinous material that bends the hair cell processes?

A

the rate of neurotransmitter release by hair cell is changed

50
Q

what does the dynamic labyrinth (semicircular canals) detect?

A

rotation of the head

51
Q

what are the receptors (cristae ampullaris) of the dynamic labyrinth?

A

epithelia containing hair cells

52
Q

where are the cristae of the dynamic labyrinth?

A

in the ampulla of each semicircular canal

53
Q

where does the stereocilia of the hair cells of the dynamic labyrinth extend into?

A

a gel-like cupula that spans the ampulla

54
Q

what does each semicircular canal connect to?

A

the vestibular sacs

55
Q

what does it mean that the semicircular canal connect to the vestibular sacs?

A

that they are rendered circular

56
Q

when the head is rotated what happens?

A

the inertia of the stationary endolymph in a semicircular duct pushes the cupula which bends the hair cell’s sterocilia the opposite direction of rotation

57
Q

what is altered when the sterocilia are bent?

A

the rate of neurotransmitter release by hair cells

58
Q

what does each semicircular canal detect?

A

rotation in one of the three planes of space

59
Q

where are sensory cell bodies located?

A

in the nearby vestibular ganglia

60
Q

what do axons continue in the vestibular branch form?

A

the vestibuloochlear nerve (VII)

61
Q

where does axons in the vestibular branch synapse?

A

in the vestibular nuclei in the medulla

62
Q

what does the vestibular nuclei also receive?

A

proprioceptive input

63
Q

what does the vestibular nuclei do? (2) (SA)

A

1) send motor commands down the vestibulopinal tracts

2) adjust muscle tone to compensate for head and neck movements and to maintain balance

64
Q

what does the vestibular nuclei relay information to?

A

the superior colliculi

65
Q

why does the vestibular nuclei relay information to the superior colliculi?

A

to keep eyes fixed during head movements

66
Q

what does the vestibular nuclei send information to the cerebellum for?

A

about body position and movement for cerebellar function

67
Q

what type of information does the vestibular nuclei send to the cerebral cortex?

A

equilibirum information

68
Q

how does the vestibular nuclei send equillibrium information to the cerebral cortex?

A

via posterior ventral nucleus of the thalamus

69
Q

why does the vestibular nuclei send equalibrium information to the cerebral cortex?

A

to provide a sense of head position and movement

Decks in ► Med - Anatomy & Physiology Class (130):