Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NSx Neuroanatomy > Auditory + Vestibular System > Flashcards

Auditory + Vestibular System Flashcards

1
Q

Components of external ear

A

Auricle

EAM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What separates the outer ear from middle ear?

A

TM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the three main chambers of the middle ear?

A

Tympanic cavity

Mastoid antrum

Eustachian tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three ossciles and what do they abut

A

TM-> malleus-> incus-> stapes-> oval window (ossicle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Contents of the middle ear

A

Nerves:

Facial nerve

Chorda tympani

Lesser petrosal nerve

Tympanic branch of the glossopharyngeal nerve (Jacobsen’s nerve)

A branch from internal carotid plexus

Ossicles

Tensor tmpani muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Roof of middle ear

A

Tegmen tympani

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Posterior wall of middle ear

A

Mastoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Anterior wall of middle ear

A

Carotid wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Lateral wall of middle ear

A

Membranous (tympanic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Floor of middle ear

A

Jugular wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Superior relation of middle ear

A

Tegmen tympani separates it from the middle cranial fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Inferior relation of middle ear

A

Jugular bulb, there can be congenital dehiscnece of floor with jugular bulb in middle ear placing it at risk of injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Medial relation of middle ear

A

Labyrinth and lateral semiciruclar canal lies posterosuperior to facial nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Posterior relation of middle ear

A

Sigmoid venous sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Anterior relation of middle ear

A

Petrous part of ICA in carotid canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Posterior relation of middle ear

A

Posteromedial to mastoid air cells- cerebellum in posterior cranial fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Compartments of the middle ear

A

Epitympanic recess/attic

Tympanic cavity

Hypotympanum-> Eustachian tube opening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Components of inner ear

A

Bony labyrinth- formed by openings in petrous portion of temporal bone

Membranous labyrinth- formed by simple epithelial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Relation between membranous and bony labyrinth

A

Membranous labyrinth lines the contours of the bony labyrinth and is filled with endolymph

The bony and membranous labyrinths are separated by perilymph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the components of the membranous labyrinth

A

Cochlea (auditory labyrinth)

Utricle, saccule and semicircular canals (vestibular labyrinth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Components of the cochlea

A

Bony core- mediolus which contains cochlear part of CN VIII

Cochelar canal which winds two and a half times around the mediolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Divisions of the cavity of the cochlear canal

A

Scala vestibuli- above

Scala media- middle

Scala tympani- below

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Endolymph is found in which scala?

A

Scala media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Perilymph is found in which scala
Scala vestibuli and scala tympani
26
How are the scala vestibuli and scala tympani in communication
At the apex of the cochlea called the helicotrema The scala media ends in a blind-ended sac
27
What separates the scala vestibuli from scala Media?
Reisnner's membrane
28
What separates the scala media from the scala tympani
The basilar membrane
29
How are Reisner's and basilar membranes attached to the bony wall of the cochlear canal?
Spiral ligament
30
What is the organ of Corti?
Composed of sensory hair cells on the scala media side of the basilar membrane Contains stereocilia that project into the overlying gelatinous structure- tectorial membrane
31
Describe how audotiry signals are transduced
Inward movement of the oval window by stapes sets up a fluid wave along scala vestibuli and scala tympani across the scala media to cause upward displacement of the basilar membrane The basilar membrane is forced up against the fixed tectorial membrane with shearing forces exerted on stereocilia causing excitation of sensory hair cells. Point of maximum displacement is determined by sound frequency displacement- low frequency= maximum near the base, high frequency- maximum near the apex. The excitability of cochlear hair cells is frequency-dependent.
32
What happens after fluid waves have crossed the scala tympani
Cause the round window membrane to move in and out
33
Which two features of the middle ear enhance the efficacy of energy transfer from air to fluid
The oval window is substantially smaller than tympanic membrane- vibratory force is greatly magnified at the fluid interface of the oval window Use of TM and ossicles reduces energy loss from higher acoustic impedance of transition from air to fluid
34
Brainstem organisation of afferent auditory fibres
Cochlear nerve fibres terminate on both dorsal and ventral cochlear nuclei which maintain tonogrpahic organisation of cochlea Dorsal cochlear nuclear fibres project axons across midline in dorsal acoustic striae-\> lateral lemnicsuc-\> inferior colliculus Ventral cochlear nuclear fibres-\> ipsilateral and contralateral superior olivary nucleus via trapezoid body. Then ascend in contralateral lateral lemniscus-\> inferior colliculus Inferior colliclus-\> MGN via inferior brachium
35
Function of superior olivary nucleus w.r.t auditory tract
Concerned with sound localisation Compares differences in the timing of sounds received and intensity Projects to the nucleus of lateral lemniscus and the inferior colliculus
36
What is the only part of the ascending auditory pathway that does not have commissural connections?
MGN
37
How do the lateral lemnisci communicate?
Via commissure of Probst
38
Electrical stimulation of the primary auditory cortex
Produces sensation of simple sounds such as buzzing or ringing
39
Electrical stimulation of the auditory association areas
Complex sounds e.g. dog barking or familiar voice
40
Organisation of auditory cortex
Tonotopicaklly Low frequency sounds anteriorly High frequency posteirorly Summation columns associated with binaural input and suppression columns monaural input
41
Clinical features of conducitve hearing loss
Reduction in hearing Maintain good ability to hear loud noises Hear better in setting of noisy backgrounds
42
Clinical features of sensorineural hearing loss
Selective difficulty hearing high pitched sounds and vowels Loss of speech discrimination out of proportion to pure tone deafness Difficulty hearing speech that is mixed with background noise
43
Low pitch tinnitus frequently associated with
Conductive hearing loss
44
High frequency tinnitus assocaited with
Sensorinueral hearing loss
45
In which condition is sensorineural hearing loss associated with low frequency tinnitus?
Meniere's
46
Subjective tinnitus
Only experienced by patient
47
Objective tinnitus
Experienced by patient and examiner
48
Causes of objective tinnitus
Eustachian tube dysfunction Ossicles Palate Cerebral vascular malformations or aneurysms
49
Weber's lateralises to right AC\>BC on right
R SNHL
50
Weber's lateralises to right BC\>AC on right
R Conductive hearing loss
51
Cochlear lesion causing high frequecny hearing loss
Base of cochlea (due to tonotopic arrangement)
52
Cochlear lesion causing low frequency hearing loss
Apex of cochlea
53
Unilateral auditory cortex lesion
Results in difficulty localising signs May make it difficult for a listener to ignore background noise or competing measures
54
Draw the ascending auditory pathway
55
Disequilibrium
Represents malfunction of one of the three communicating systems- visual, proprioceptive, vestibular
56
Basic function of vestibular system
Coordination of motor control Posture Equiibrium Eye movements
57
What structures constitute the vestibular portion of the labyrinth
Utricle Saccule Semicircular canal
58
Function of utricle and saccule
Detect linear acceleration and the position of the head in space
59
Structure of utricle and saccule
Dilatation of membranous labyrinth, surrounded by perilymph Filled with endolymph and lined by simple cuboidal epithilium except at receptor rich areas called maculae
60
Components of the utricle and saccular maculae
Supporting cells- columnar epithelial cells continuous with the simple cuboidal epithelial cells that line the utricle and saccule Hair cells which are specialised receptors cells intercalated between the supporting cells Otolithic membrane (gelatinous mass embedded with calcium carbonate otoliths) that covers hair cells Dendrites of cells in the vestibular ganglion
61
Arrangement of macular hair cells
Hair of maculae are microvilli each containing 40-80 with a single kinocilium that arises from a centriole. One kinocilium is located in the periphery of each hair cell, thus polarising the hair cell
62
Polarisation of utricular and saccular maculae
Kinocilia of the maculae are arranged to polarise the maculae in relation to an imaginary curved line called the striola Utricular maculae are polarised towards the striola Saccular maculae are polarised away from the striola
63
Functional significance of the otolithic membrane
Exerts gravitational pull on hair cells. The orientation of the hair cells relative to this gravitational force determines the direction of their displacement Displacement of hair cells along the axis of polarisation depolarises the cells and initiates excitatory impulses Displacement of hair cells in the direction opposite hyperpolarises the cells and initiates an inhibitory impulse
64
Plane of saccule
Vertical
65
Plane of utricle
Horizontal
66
The function of semicircular ducts
Provide information bout the angular acceleration fo the head in any direction but do not detect its ability in a static position
67
Functional significance of the semicircular canal
Each duct enlarges at point of attachment to the utricle- ampullae which are the functional counterparts of the maculae Contained thickened sensory epithelium called ampullary crest which contains kinocilia containing hair cells These hair cells are embedded in a gelatinous mass- the cupula and fill space between crest and roof of the ampulla Angular acceleration of the head causes displacement of endolymphatic fluid and movement of cupula causing stimulation of hair cells.
68
Cupula vs otolithic membrane
Cupula lacks calcium carbonate crystals
69
Central projections of vestibular system
Spinal cord Cerebellum Nuclei controlling EOMs
70
Scarpa's ganglion
Vestibular ganglion which lies at the base of the IAC
71
Through which cerebellar peduncle to vestibular fibres pass
Inferior cerebellar peduncle
72
Longitudinal vestibular spinal tracts
Vestibulospinal tract MLF Direct fibres
73
Medial vestibulospinal tract
Originates in medial vestibular nucleus, projects corssed and uncrossed fibres in the desecending MLF as far as the cervical spinal segements
74
Lateral vesteibulospinal tract
Arises in lateral vestibular nucleus (Deiter's nucleus) Projects uncrossed fibres to all levels of the SC
75
Deiter's nucleus
Lateral vestibular nucleus Sends fibres to lateral vesitbulospinal tract
76
Where do vestibulospinal tract fibres terminate
Rexed Laminae VII and VIII which facilitate extensor muscles Provide physiological basis for maintenance of extensor muscle tone required for upright posture
77
Direction of nystagmus
Named for fast phase It is actually the direction of slow phase that is pathological with the fast phase representing corrective compensatory eye movements
78
Visual fixation and nystagmus
Visual fixation inhibits peripheral vestibular nystagmus
79
Differentatiating factors between peripheral and central nystagmus
Central- multidirectional without inhibition by fixation
80
Destructive peripheral nystagmus Fast phase to right
Unopposed tonic firing of right labyrinth-\> slow gaze to left with corrective movements to the right (fast phase to right) Left-sided pathology
81
Signs and symptoms of peripheral vestibular pathology
Pathology affecting vestibular labyrinth or ganglia May present with hearing loss, tinnitus, aural fullness, and or pain Facial weakness and hearing loss if a ganglial lesion Past-pointing on the affected side Rotatory nystagmus inhibited by visual fixation Associated autonomic symptoms may be seen
82
Central vestibular lesions
CPA lesions: Hearing loss and tinnitus Loss of corneal reflex Facial weakness Ipsilateral ataxia and intention tremor Brainstem and cerebellar Mild vertigo Other CN palsies- diploploia, dysarthria, perioral numbness Long tract signs Hearing loss and tinnitus absent
83
Location of peripheral vestibular lesions
Labyrinth Ganglia
84
Vestibular labyrinth lesions
Episodic vertigo Hearing loss, tinnitus, aural fullness Otalgia On examination patient points towards the affected side On examination, patient points to the affected side Spontaneous nystagmus with fast phase away from the affected side, rotatory and inhibited by fixation Prounced symptoms with nausea and vomiting
85
Lesions in vestibular ganglia and nerve at IAC
May have facial weakness due to close proximity to facial nerve Hearing and tinnitus often present but vertigo less prominent and aural fullness/otalgia absent
86
Central vestibular lesions location
CPA and brainstem
87
CPA lesions
Progressive hearing loss and tinnitus Loss of ipsilateral corneal reflex and facial numbness Facial weakness Ipsilateral ataxia and intention tremor Contralateral hemiparesis and hemisensory loss Vertigo, nystagmus and autonomic symptoms mild
88
Brainstem and cerebeullm vestibular lesions
Isolated vestibular lesions are rarely the result of lesions in brainstem or cerebellum Vertigo associated with diploplia, dysarthria, perioral numbness Long tract signs Hearing loss and tinnitus typically absent
89
Localisation of gaze evoked nystagmus
Non-localising
90
Downbeat nystagmus DC
Cervicomedullary junction | (posterior fossa)
91
Upbeat nystgamus UV
Vermis
92
Localising nystagmus
Should be in primary position, not gaze evoked
93
Convergence retraction CD
Dorsal midbrain
94
Seesaw nystagmus ST
Third ventricular/parasellar region
95
Brun's nystagmus BC
CPA
96
Difference between rebound and periodic alternating nystagmus
PAN alternates side to side with periodicity Rebound is gaze-evoked
97
What is the location of the cochlear?
B
98

NSx Neuroanatomy (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions