Hearing, taste and smell Flashcards
wavelenght determines what of sound
pitch
amplitude determines what of sound
intensity
basic sound transduction pathway
- sound waves hit tympanic mem and become vibrations
- sound wave energy transferred to 3 middle ear bones, which vibrate
- stapes attached to membrane of oval window. vibrations of OV cause fluid waves in cochlea.
- fluid waves push on flexible membranes of cochlear duct - hair cells bend and release neurotransmitter
- neuroT release onto sensory neurons –> APs travel through cochlear nerve to brain
- energy from waves tranfers across cochlear duct –> tympanic duct –> dissipated back into middle ear at round window
three middle ear bones
malleus
incus
stapes
where is perilymph (x2)
endolymph
perilymph found in vestibular and tympanic duct (above and below cochlear)
endolymph in cochlear duct
external auditory meatus supplied by which nerves
auricular branch of vagus
auriculotemporal branch fo trigeminal
which of the 4 tympanic membrane quadrants is safest to put a grommet
why would you put in a grommet
antero-inferior
(chorda tympani is in the postero-superior quadrant
put grommet in if otitis media with effusion
which part of which ossicle sits on tympanic membrane
handle of malleus
two muscles in middle ear cavity and their movements
tensor tympani muscle (pulls ear drum medially, tenses tympanic mem, less vibration) stapedius muscle (pulls base of stapes away from oval window so not all vibrations are transferred - protective)
nerve transmission from ear drum
sound waves hit ear durm transferred in cochlear n connected to chorda nuclei connected to olivary nucleus connected to motor nucleus of CN7 and CN 5
middle ear muscles supplied by (each)
tensor tympani supplied mandibular nerve of trigeminal
stapedius muscle supplied by facial
loss of function of middle ear muscles
tinnitis and hyperacusis (loud)
which muscles contract to open pharyngotympanic tube
tensor veli palatini
salpingopharyngeus
what is in the vestibule of the inner ear
utricle
saccule
what three things are in the bony labyrinth of inner ear
vestibule
semicircular canals
cochlea
what membrane inside cochlear changes thickness
basilar membrane - allows differentiation of frequencies
shorter frequencies travel further
where is frequency signal detected
organ or corti
upward deflection of basilar mem –> moves inner/outer hairs laterally to tectorial mem
outer cells inc sensitivity of inner hair cells
what causes signal transduction in cochlea
displacement of sterocilia oopens K channels
what does kanamycin do
kills outer hair cells at specific point along cochlea - specific frequ hearing loss
conductive hearing loss on Rinne and Weber
Rinne: bone conduction > air on affected side
Weber: sound louder on affected side
normal hearing on rinne and weber test
rinne: air > bone
weber: same on both
sensori-neural hearing loss rinne and weber
rinne: air > bone
weber: sound louder on normal ear
three types of tongue papillae
valate (along sulcus terminalis, supplied by glossopharyngeal n.)
foliate (poorly developed)
fungiform (most numerous supplied by facial nerve)
taste from anterior 2/3 of tongue detected by who
sensory neurons in geniculate ganglion of facial n
= chorda tympani branch (travels with lingual nerve –> infratemporal fossa –> petrotympanic fissure –> middle ear cavity –> joins facial nerve)
taste from posterior 1/3 of tongue
sensory neurons in inferior ganglion of glossopharyngeal n
neurons conveying taste (facial, glossopharyngeal and vagus) journey to cortex
3 form tractus solitarius
–> synapse in nucleus of tractus solitarius (gustatory) –> axons cross midline –> join medial lemniscus –> synapse in thalamus –> cortex
olfactory receptors
bipolar neurons in olfactory epithelium –> axons go through cribriform plate of ethmoid of skull to olfactory bulb –> many brain location
