physiology Flashcards
what is sound
pressure wave caused by oscillating molecules set in motion by a vibration
what range of sounds can humans hear
20-20,00Hz
what dictates pitch
frequency of wave
what dictates intensity
amplitude of wave
what is used to assess hearing range
audiogram
what role does the external ear play in hearing
functions as a receiver due to its shape
what role does the middle ear play in hearing
functions as an amplifier
what within the middle ear amplifies sound, how much is the sound amplified by
ossicular chain
amplified by 20-25dB
what are the two openings of the cochlea, what are their function
oval and round window
permit transmission of the pressure wave in the canal and the vibration of the basilar membrane
what is the function of the inner ear in hearing
receiver/transducer
how is hearing function tested in universal newborn hearing screening
The outer hair cells in the organ of corgi produce sounds called outer acoustic emissions (OAEs) but if OAEs are absent this suggests a problem with hearing.
what does the vestibulospinal tract allow us to do with regards to balance
balance with our eyes shut
how can the vestibulospinal tract function be tested
romberg test (close eyes and see if they can balance)
what does the vestibule-ocular reflex allow us to do with regards to vision
vision remains still even if the head moves from side to side
what does damage to the vestibule-ocular reflex result in
nystagmus
what is oscillopsia, what causes it
patient experiences constant vertigo as they are unable to focus while moving
this is due to NO vestibular input
what are the receptors for taste and smell
chemoreceptors
what is the sense organ for taste
taste buds
what is the lifespan of taste buds
10 days
where are taste buds located, where are the majority found
tongue, palate, epiglottis and pharynx
majority - papillae in the tongue
what are papillae
finger-like structures which gives the rouge appearance on the tongue surface
what are the 4 types of papillae, which contain taste buds
Filiform = most numerous,
Fungiform
Vallate
Foliate
all contain taste buds apart from filiform
what are taste provoking chemicals called
tastants
what nerves are involved in transmitting taste to the brain
VIIth (chorda tympani branch of facial nerve) = anterior 2/3rd tongue
IXth = posterior 3rd of tongue
Xth = areas other than tongue e.g. epiglottis and pharynx
what are the 5 tastes
salty sour sweet bitter umami (meaty or savoury)
what causes a salty taste
stimulation by chemical salt especially sodium chloride
what causes a sour taste
stimulation by acids which contain free H+ ions
what causes a sweet taste
stimulation by glucose
what causes a bitter taste
stimulated by lots of tastants (e.g. toxic plants, poison)
what causes a umami taste
trigger by amino acids especially glutamate
what is ageusia, what causes it
loss of taste function caused by:
nerve damage
local inflammation
some endocrine disorders
what is hypogeusia, what causes it
reduced taste function caused by:
chemo
medications
what is dysgeusia, what causes it
distortion of taste caused by:
medications chemo zinc deficiency dental issues URTI reflux glossitis
what are olfactory receptors, where are they located
specialised ending of renewable afferent neurones within the olfactory mucosa
what is the lifespan of olfactory receptors
2 months
what is the olfactory mucosa
patch of mucosa in the dorsal roff of the nasal cavity
what 3 cell types are found in the olfactory mucosa, what are their functions
olfactory receptors = detect smells
basal cells = secrete mucus
supporting cells
how do impulses from the olfactory receptors reach the brain
receptors to olfactory nerve which pierces the cribriform plate of the ethmoid bone which enters the olfactory bulbs in the inferior surface of the brain. the bulbs then transmit to the brain
what must a substance to in order to be smelled
sufficiently volatile = must enter nose with inspired air
sufficiently water-soluble = to dissolve in the mucous coating of the olfactory mucosa
what do olfactory receptors detect
odourants
how do odourants reach the receptors normally, how can this be enhanced
via diffusion as the olfactory mucosa in above the normal path of airflow
sniffing = draws air upwards to the mucosa
what is anosmia, what causes it
inability to smell caused by:
viral infection
allergy
nasal polyps
head injury
what is hyposmia, what causes it
reduced ability to smell caused by the same things as anosmia
may be an early sign of parkinson’s
what is dysosmia, what causes it
altered sense of smell caused by:
different interpretation of odours
hallucinations of smell
what lines the external auditory canal
epidermis
what lines the auditor meatus
epidermis
what lines the middle ear
columnar lined mucosa
what structures does the middle ear contain
ossicles
opening to the eustachian tube and mastoid cavity
what are the 3 ossicles
malleus
incus
stapes
what is the nose lined by
nasal vestibule = squamous epithelium
rest of nose = pseudostratified ciliated columnar epithelium (respiratory epithelium)
what is the throat lined with
squamous or pseudostratified ciliated columnar epithelium
what are the adenoids made of
ciliated pseudostratified columnar cells which transitions into stratified squamous within deep folds.
what are the tonsils made of, what do they contain
specialised squamous cells
contain deep crypts and lymphoid follicles
what are the 2 components of salivary glands
acinar = secretory system ductular = drainage system
what are the 3 types of cell found within the salivary glands , how do they stain
serous cells = stain dark
mucinous component = stain clear grey
peripheral myopeithelial cells
what do serous cells contain
digestive enzymes including amylase
what is a pure tone threshold at a specific frequency
the decibel level at which the sound is heard 50% of the time
what colour is all feedback from the RIGHT ear on audiograms
red
what colour is all feedback from the LEFT ear on audiograms
blue
what symbol is used to signify RIGHT air conduction on audiograms
circle
filled in circle = masked air conduction
what symbol is used to signify RIGHT bone conduction on audiograms
triangle
[ = masked bone conduction
what symbol is used to signify LEFT air conduction on audiograms
X
filled in circle = masked air conduction
what symbol is used to signify LEFT bone conduction on audiograms
triangle
] = masked bone conduction
