l10 ear Flashcards
external auditory meatus
s shape (prevent flies going in)
2.5 cm length
amplify 3kHz
Tympanic membrane
- Lie obliquely
- Slightly concave
- 0.1 mm thick
8 to 10 mm diameter
middle ear include
3 ossicles (incus, malleius, stapes)
2 muscle (stapedius + tensor tympanic)
joint between incus and stapes
movevable joint, for amplifying sound
stapedius + tensor tympanic func
dampening sound
stapedius, pull stapes away from oval window
tensor put tension on malleus (vibrate less)
nerve stapedius
facial 7
nerve tensor tympanic
mandibular of trigeminal 5
2 muscle is reflex, how?
when loud noise enter, signal send to brainstem and send decision back for these muscle to dampen sound
-> 40 msec delay
-> you still hear very loud at the first 40 msec (not significant unless SUPER LOUD - GUN SHOT SOUND)
Bony Labyrinth
hard-walled bony cavities
-= INCLUDE LOW K+ PERILYMTH
Membrane Labyrinth
INSIDE BONY
- inside these include endolymph (high k+)
Cochlea is where mechanical (vibration) signal -> electrical (impulses) -> transduction
describe?
Coils 2.5 times around modiolus
10mm in size
25mm uncoiled
hair cell at cochlear, has axon goin to brain,
Cochlea duct
partition, separating the cochlea into 3 spaces
scala med
(peri)
Above call
scala vestibulli (endo)
Below cal
scala tympanic (endo)
Helicotrema
fluid of scala vestibuli and tympani are continuous
membrane separate media from scala tympanic
basilar membrane
on top basilar is
organ of corti
organ of corti has
lots of tissues connect each other there, lots of haircell here too
3 out
1 in
low freq to what hair cell
near apex
high freq to what hair cell
near base (narrow)
what we haer conciously from
inner hair cell
basilar has haircell send signal to
cranial 8
open
k+ get inside, making action potential????? check again
amplitude and pattern
Each neuron has different threshold
Amplitude increase -> number of neuron activate by hair cell increase
Ø Pattern of neuron send signal to brain (sound intensity)
superior olive function
utilise that sound arrive at slightly different time
- > calculate angle/location of sound
-> horizontal
dorsal path of
verticle sources of sound
- delay between direct and reflected sound, how it bounce through pinna
inferior colliculi
- Auditory map
- Analyse pattern of sound: know by pattern of sound if it is female or….
- Processing complex sound and handling echoes, just take the first signal and remove others
central auditory pathway
vestibulacochlea nerve -> cochlear nuclei ->
dorsal: to inferior coliculous
ventral: to bilateral superior olivary or lateral leminicus to inferior coliculous
to medial geniculate nuclei -> cortex
medial SO
calculate angle, which ear sound came from (horizontal claim)
inferior
vertical sources of sound, based on how sound bounce in pinna, direct or indirect
inferior colliculi func
map of sound (where sound is form)
analyse pattern of sound: familiar? female voice?
handling echoes
primary cortex func
receiving both ears
secondary left func
meaning comprehension
secondary right function
non verbal aspect, emotional
