taste Flashcards
Receptors of taste and smell
chemoreceptors
sensory receptor cells of taste
packaged in taste buds
sense organ of taste
taste buds
what do taste buds consist of
sensory receptor cells and support cells arranged like slices of orange
life span of taste recepotr cells
10 days
what are taste receptor cells replaced from
basal cells within the taste buds
what do taste receptor cells synpase with
afferent nerve fibres
where do majority of taste buds sit
papillae in the tongue
papillae
finger-like structures which gives rise to the rough appearance of the dorsum of the tongue
4 types of papillae
filiform
fungiform
vallate
foliate
which papillae dont contain taste buds
filliform
what does binding of taste to receptor cells produce
depolarising receptor potential
what does receptor potential initiate
action potentials in afferent nerve fibres whcih synapse with receptor cells
how do afferent taste fibres reach the brainstem
via
VIIth cranial nerve (chorda tympani branch of facial nerve) - anterior two-thirds of the tongue
IXth cranial (glossopharyngeal) nerve - posterior third of the tongue
Xth cranial (vagus) nerve - areas other than tongue, including e.g. epiglottis and pharynx
five primary tastes
bitter
sour
salty
sweet
savory
ageusia
loss of taste functionhy
hypogeusia
reduced taste function
dysgeusia
distortion of taste function
whihc nerve has a protective effect
cn v
what nerve mediates the common odours
cn i
during quiet brrathing how do odorants reach smell receptors
by diffusion
what must a substance be to be smelled
sufficenelty volatile
sufficiently water soluble
what must the odourant be before neural conduction can occur from olfactory cleft to brain
pass to olfactory cleft
move from air phase to aqeuous phase
lifespan of olfactory receptors
2 months
olfactory receptor function
detect odours
olfactory receptor steps
Pierce the cribriform plate and enter the olfactory bulbs synapse with 2nd order neurones in the olfactory bulb
Complex transformation of chemical energy into a neural signal (glutamate and dopamine)
Olfactory bulbs transmit smell information to the brain
From the olfactory bulb neurons passes along the olfactory tract to reach temporal lobe and olfactory areas
ansomia
inability to smell
hyposmia
reduced sense of smell
dysosmia
altered sense of smell
phantosmia
smell percieved in absence of stimulus
objective smell testing
UPSIT
