N21 Taste and smell Flashcards
what is the role of olfactory/ taste system?
nutrient detection
toxin avoidance
how does the sense of smell reach olfactory bulb?
sensory axons pass through cribriform plate to make synaptic contact in olfactory bulb
what are the 7 classification of odours?
flowery, etheral, musky, camphorous, sweaty, rotten and pungent
in olfactory transductiom how is an olfactory receptors excited?
substance must be volatile and soluable in mucous
where are the olfactory receptor molecules?
on cilia
how do the receptor molecules reach depolarisation?
each receptor protein coupled to a G protein that activates adenyl cyclase, cyclic AMP rises, opening K channels leading to depolarisation (threshold)
each cell responds to several odours, but favours one only
list the papillas on the tongue?
filiform
folate
fungiform
circumvalate
whice taste buds are mediated by taste?
folate
fungiform
circumvalate papillae
what is a risk of third molar surgery?
damage to chorda lingual nerve, lose sense of taste from anterior 2/3 of tongue, taste buds atrophy
will return if chorda lingual nerve recovers
list the 5 basic tastes
sweet sour salty bitter umani (pleasant)
what is the recognition concentration of salt and sweet?
0.01 mol/l
what is the recognition concentration of sour?
0.0023
what is the recognition concentration of olfaction?
almost impossible to calculate
likely only one odour molecule needed per olfactory cell
what is the central pathway of taste?
- afferent nerve to medulla
- nucleus of the tractus solitarius
- thalamus
- post central gyrus
- somatic area for tongue
central pathway for smell?
- bipolar cell through cribriform plate
- olfactory bulb
- ipsilateral olfactory cortex via olfactory tract
- contrlateral olfactory cortex via anterior commisure
