Physiology of Taste and Smell Flashcards
what type of receptor is responsible for taste and smell?
chemoreceptors
where are the sensory receptors for taste and smell primarily located?
tastebuds
what are the sense organs for taste?
tastebuds
where are the tastebuds primarily located?
papillae on the tongue
palate
epiglottis
pharynx
lifespan of tastebuds?
10 days
what nerves are involved in taste sensation?
CN7
CN9
CN10
what do the axons of olfactory receptors form?
afferent fibres of the olfactory nerve
what influences taste perception?
information from olfactory receptors
name the 2 types of cells present in the taste bud
sensory receptor cells
support cells
what cells are responsible for replacing old taste receptor cells?
basal cells
what is the only type of papillae not to contain tastebuds?
filliform
name the 4 types of papillae from anterior to posterior
filliform
fungiform
foliate
vallate
which is the most numerous of papillae on the tongue?
filliform
how does the taste signal get to cranial nerves?
tastant binds to receptor cells in the taste bud = depolarisation
causes AP in afferent nerve fibres which is conveyed to cranial nerves
where is the end-point of the taste signal?
cortical gustatory cortex
where does CN8 receive taste fibres from?
anterior 2/3rds of tongue via chorda tympani nerve
where does CN9 receive taste fibres from?
posterior 1/3 of tongue
where does CNX receive taste fibres from?
anywhere other than the tongue
name the 5 primary tastes
sweet salty sour bitter umami (meaty/savoury)
what is ageusia?
loss of taste function
name given to reduced taste function?
hypogeusia
name given to distortion of taste function?
dysgeusia
causes of taste abnormalities/function?
glossutus gum infection tooth decay URTI meds chemo neoplasm
3 cell types present in the olfactory mucosa?
olfactory receptor cells
supporting cels
basal cells
what cells of the olfactory mucosa secrete mucus?
basal cells
organise the structure of an olfactory neurone from proximal to distal:
olfactory receptor
dendrite
olfactory cilia
olfactory bulb
bulb
receptor
dendrite
cilia
lifespan of olfactory recpetors?
2 months
which part of the olfactory dibres forms afferent fibres of olfactory nerve?
axons of olfactory receptors
what do olfactory bulbs do?
transmit smell information to brain
what to the neurons after the olfactory bulb?
pass along olfactory tract to temporal lobe
by what process do odorants reach the smell receptors in passive breathing?
diffusion
how can the process of smell be sped up?
sniffing
define anosmia?
inability to smell
what is hyposmia
reduced abiity to smell
what abnormality of smelling could indicate early parkinsons?
hyposmia aka reduced ability to smell
how would you define an altered sense of smell medically
dysosmia
