Physiology Flashcards
(24 cards)
What dictates the pitch and the volume of sound?
pitch- frequency of sound
volume- amplitude of sound
What frequency can humans hear?
20Hz-20000Hz
What part of the anatomy focusses the sound?
- tympanic membrane to oval window
- malleus handle to incus long process
What are the parts of the cochlea?
the scala media is suspended between the scala tympani and the scala vestibuli
What are perilymph and endolymph most like?
perilymph = ECF endolymph = ICF
How is the cochlea arranged in terms of frequency?
tonotopically so each frequency of sound vibrates a different part of the basilar membrane
What is the pneumonic for auditory brainstem response tracking?
Eight cranial nerve Cochlear nucleus Olivary complex (superior) Lateral lemniscus Inferior colliculus E.coli
What is the area of the brain for hearing and speech?
left posterior superior temporal gyrus
What is the resting state for the cartilaginous portion of the Eustachian tube and how is it opened or closed?
- resting is closed
- can be opened by tensor veli palatini and levator palatine muscles
What are the milestones for hearing in utero?
In utero: 18 weeks a foetus can hear
In utero: 26 weeks a child kicks and responds to sound
What are the milestones for hearing/speech?
3 months: cooing, recognise mother voice
6 months: babbling, turns to sound
12 months: simple noises
12-24 months: syllable deletion and simplification, substitutions
18 months: 20-50
24 months: 50+ words, understands questions
What are the features of Romberg’s test?
- balance with eyes closed
- input is vestibular
- output is vestibulospinal
What supplies the SCCs, utricle and saccule?
- SVN supplies the lateral, anterior SCC and utricle
- IVN supplies posterior SCC and saccule
What are the features of the hair cells in inner ear?
- Kinocilium is the longest
- Stereocilia are the rest
- deflection towards increases APs
- deflection away decreases APs
How do the SCCs work with head movement to move eyes?
- cupula senses movement by perilymph movement
- excitation of muscles on the side of movement
- inhibition of the other side
- input is vestibular
- output is vestibulo-ocular
What happens if there is a lesion on the left to eye movement?
if you lose left function, the eyes are moving to the left and then fast back to the right
What are the features of taste receptors?
- chemoreceptors
- lifespan of 10 days
- pore and protective microvilli
- synapse with afferent nerve fibres
Where are the taste buds on the tongue?
fungiform, vallate and foliate papillae
What are the nerve outputs for taste?
- 7th CN for the anterior 2/3rds tongue vie chord tympani
- 9th CN for posterior 1/3rd tongue
- 10th CN for everywhere else
What are the five tastes?
bitter, sour, salty, sweet and umami
What are aguesia, hypoguesia and dysguesia?
- Aguesia is loss of taste function eg nerve damage, radiation, tobacco
- Hypogeusia is reduced taste function eg chemotherapy
- Dysgeusia is distortion of taste function eg chemotherapy, metronidazole, infections
How does smell work?
- sensed in the olfactory mucosa
- afferent fibres of olfactory nerve run through cribriform plate of ethmoid bone and enter olfactory bulbs
- to olfactory tracts to temporal lobe
- smell must be volatile and water-soluble
What are anosmia, hyposmia and dysosmia?
Anosmia is inability to smell eg allergy, infection, polyps
Hyposmia is reduced ability to smell eg above or Parkinson’s
Dysosmia is altered sense of smell
What is congenital deafness in a 2 year old most likely to be?
cytomegalovirus in the mother in early pregnancy
