Ear Flashcards
Outer ear made of
1/3 cartilage
2/3 bone
What can block rust schism draining from middle ear
Adenoid tonsils
Middle ear bones chain
Malleus
Incus
Stapes
What muscles in middle ear
And innervation
Tensor tympanic muscle (attaches to malleus- innervated by cnV3 )
Stapedius (attaches to stapes— innervated by cn7)
Joints between middle ear bones
Sinovial
Middle ear and outer ear amplification??
Outer quietens certain sounds
Middle amplifies
- SA as tympanic membrane is larger than stapes
- lever action of malleus
How many turns for cochlea
2.5
Stapes goes to which window
Oval
Scala vestibule and scala tympani
Which has high…
Perilymph
high na+
What’s in between scala vestibule and scala tympani
Scala media// cochlear duct
Scala media/ cochlear duct filled with
Endolymph
High k+
Organ of corti where
Scala media
Basilar membrane base=
Detects what
Narrow stiff
High freq
Basilar membrane apex
Detects what
Floppy, wide
Low freq
Hair cells inner and outer
Their movement does what
Inner= mechanical transduction
Outer = fine tuning
Movement depolarises cell so glutamate neurotransmitter released
What nerve fibre takes signal from neurotransmitter
Cn8 vestibulocochlear
Cn8 takes signal where
Central auditory pathway — ECOLI
EIght nerve Cochlear nucleus Olive Lateral leminiscus Inferior colliculus
medial geniculate body
primary auditory cortex (I’M Auditory)
Locating sounds wherrre
Olive nucleus
Otolithic organs
Utricle - horizontal plane
Saccule - verticals plane
Contain viscous endolymph and hair cells
Detect gravity and acceleration
Semicircular canals
Ring filled with viscous endolymph and cupula at base stretches to cilia
Detect rotation accel and deccel
Head then moves opposite to endolymph
Horizontal semicircular canal
Tennis match
Superior semicircular canal
Nodding
Posterior canal
Ear to shoulder
Cold water reflex
Eyes move slowly towards cold water ear then jump back away to normal
