1
Q
role of external ear
A
receives sound waves
2
Q
role of auricle
A
funnels sound waves through internal meatus
3
Q
middle ear
A
sound waves –> mechanical waves
4
Q
inner ear
A
mechanical waves –> electrical waves
5
Q
tympanic membrane
A
eardrum
6
Q
how are external and middle ear separated
A
tympanic membrane
7
Q
external auditory canal
A
transmits sound waves towards the tympanic membrane
8
Q
how does middle ear communicate with nasopharynx
A
auditory tube / Eustachian tube
9
Q
smallest bones in the body
A
ossicles
10
Q
ossicles
A
malleus
incus
stapes
(MIS)
11
Q
role of ossicles
A
vibrate to transmit sound waves
12
Q
location eustachian tube
A
connects nasopharynx to middle ear
13
Q
how does the Eustachian tube change as we get older
A
as a child it is more vertical
becomes more horizontal as we group
(why children are more prone to ear infections)
14
Q
functions of eustachian tube
A
- ventilation
- drainage
- allows for equilibration of pressure between atmospheric and internal environments
15
Q
why do ears hurt on an aeroplane
A
- rapid change in pressure
- ears cannot adjust in time
- eustachian tube remains closed
16
Q
why is the middle ear a high risk space
A
- connected to nasopharynx (prone to infection)
- connection to mastoid air cells
- inferior jugular vein lies inferior (risk of thrombosis)
- internal carotid artery lies anterior (pulsatile tinnitus)
- traversed by chordates tympani and facial canal (infection risk)
17
Q
pulsatile tinnitus
A
can hear a noise which matches the heart rate
- occurs in hypertension sometimes
18
Q
where is the vestibular system located
A
inner ear
19
Q
location of inner ear
A
petrous part of the temporal bone
20
Q
vestibular system
A
- vestibule
- semicircular canals and semicircular ducts
balance and equilibrium
21
Q
cochlea and cochlear ducts role
A
hearing
22
Q
special sense organs in the inner ear
A
- vestibular system
- cochlear and cochlear ducts
23
Q
cochlear
A
snail shaped structure which detects sound frequencies
24
Q
where can lower sound frequencies be detected
A
apex of the chochlea
25
where can higher sound frequencies be detected
nearer the base of the cochlea
26
fluid filled cavities within the inner ear
- bony outer labyrinth
| - membraneous inner labyrinth
27
bony outer labyrinth
contains perilymph (like extracellular fluid)
28
membraneous inner labyrinth
contains endolymph (like intracellular fluid)
29
role of the cochlear duct
separates cochlea into two chambers:
- scala vestibuli (inner)
- scala tympani (outer)
30
location of perilymph
inside chambers
31
location of endolymph
inside cochlear duct
32
helicotrema
the two chambers are continuous at the apex of the cochlea through a narrow slit, the helicotrema
33
how is sound created
- vibration of stapes creates hydraulic pressure at the apex of the cochlea (helicotrema)
- here, SV and ST meet
- vibrations descent via ST to the round window
- perilymph moves around the bony cochlea, deforming endolymph inside the cochlear duct
- the cochlear duct contains the spiral organ of Corti
- Spiral organ of Corti is stimulated by the deformation of the cochlea duct
- converts fluid pressure into electrical signals
- via the vestibulocochlear nerve (VN8)
34
location of tectorial membrane
above hair cells
35
location of basilar membrane
below hair cells
36
how is the spiral organ of corti stimulated
- cochlear duct deforms
- tectorial membrane moves up and down
- cilia on hair cells detect this
- ion channels open and there is transmission of information
- fluid pressure into electrical signals
37
auditory pathway
- polysynaptic
| - bilateral
38
1 auditory fibres
- Axons of bipolar neuron in spiral ganglion form the cochlear division of the vestibulocochlear nerve (CNVIII)
- Connect to hair cells
39
where do primary and secondary auditory fibres synapse
dorsal and ventral cochlear nuclei
40
cochlear nuclei
- receives afferents from cochlear nerve
| - projects bilaterally to superior olivary nucleus
41
trapezoid body
crossing over midline
42
what information does the superior olivary nucleus recieves
bilateral auditory information
43
where does the superior olivary nucleus send information to
ascending fibres to inferior colliculus of the midbrain via the lateral lamniscus bilaterally
44
auditory part of the thalamus
medial geniculate nucleus
45
brachium
connects thalamus to inferior colliculus
46
location of inferior colliculus
tectum of the midbrain
47
what happens at the inferior colliculus
- receives lateral lemniscus
- may exchange auditory information via the inferior colliculus commissure
- Sends auditory information to MGN via the brachium (arm) of the inferior colliculus
48
what happens at the medial geniculate nucleus
sends fibres to primary auditory cortex
49
auditory pathway
- hair cells send neurones to the spiral ganglion
- at spinal ganglion, cochlear part of vestibulocochlear nerve projects to cerebellopontine angle where cochlear nuclei is located
- synapses with second order neurones in dorsal and ventral cochlear nuclei
- projects bilaterally to superior olivary nuclei (crossing over of some neurones)
- synapses and sends ascending fibres to inferior colliculus of the midbrain via the lateral lemniscus
- synapses and neurones travel from IC to MGN via the brachium
- neurones travel from MGN to primary auditory cortex
50
where does CN8 enter the brainstem
cerebellopontine angle
51
which part of the primary auditory cortex does low frequency sound project to
anterolateral part (Low = anteroLateral)
52
which part of the primary auditory cortex does high frequency sound project to
posteromedial part = base
53
cause of Broca's aphasia
stroke to anterior branches
54
cause of Wernicke's aphasia
stroke to posterior branches
55
secondary auditory area
specialised for linguistic function
| Wernickes area
control
flashcards
Decks in class (38)
# Cards
-
1 - front of neck86
-
L1 - intro to the human brain47
-
2 - face and skull121
-
intro to cns terms22
-
L2 - the skull47
-
L3- Brain, Meninges72
-
L4 - blood supply to the brain64
-
L6 - brainstem and cerebellum106
-
L7: cranial nerves133
-
L8 - forebrain65
-
L9 - localisation82
-
L10 - vertebral column97
-
L11 - spinal cord and spinal nerves69
-
L12 - back pain39
-
L13 - ascending pathways64
-
L15/16 - stoke and TIA62
-
L14 - descending pathways62
-
L17 - autonomic nervous system49
-
L18 - the skin70
-
L19 - headaches49
-
L20 - epilepsy71
-
L21 - somatosensory disorders23
-
L22 - intracranial tumours21
-
L24 - tumours of CNS8
-
L23 - oncology for CNS tumours20
-
L25 - spinal reflexes26
-
L26 - muscle weakness43
-
L27 - pain34
-
L27 - pain prelecture12
-
L28 - cerebellum44
-
L29 - knowing pain35
-
L30 - local anaesthetics50
-
L31 - general anaesthetics58
-
L32 - visual pathways82
-
L33 - visual defects59
-
L34 - visual defects 235
-
L35 - auditory pathway55
-
L36 - MS28
