Physiology of Smell and Taste Flashcards
how are chemoreceptors stimulated
binding to particular chemicals
where are the sensory receptors for taste mainly packaged
taste buds
what are the sense organs of taste
taste buds
what do taste buds consist of
sensory receptor cells and support cells
how long is the life span of a taste bud
10 days
what are taste buds replaced by when their life cycle runs out
basal cells within taste buds
what do taste receptor cells synapse with
afferent nerve fibres
where are taste buds mainly present
tongue, palate, epiglottis and pharynx
where do the majority of taste buds sit
papillae of tongue
what do papillae appear as
little raised red dots
what are the 4 types of human papillae
filiform, fungiform, vallate, foliate
what are the most numerous type of human papillae
filiform
what type of human papillae doesn’t contain taste buds
filiform
what does the binding of taste provoking chemicals (tastant) to receptor cells cause
depolarising receptor potential
what does the receptor potential initiate
action potentials in afferent nerve fibres which synapse with receptor cells
where are signals conveyed to
cortical gustatory areas in brain
what do afferent taste fibres reach the brainstem via
7th (chorda tympani branch), 9th and 10th cranial nerves
what section of the tongue does chorda tympani sense from
anterior 2/3
what section of the tongue does glossopharyngeal nerve sense from
posterior 1/3
where does vagus nerve sense from
areas other than tongue e.g epiglottis and pharynx
what are the 5 types of taste
bitter, sour, salty, sweet, umami
what are the three abnormalities of taste
ageusia, hypogeusia, dysgeusia
what does ageusia mean
loss of taste function
what can cause ageusia
nerve damage, local inflammation or some endocrine disorders
what does hypogeusia mean
reduced taste function
what can cause hypogeusia
chemo, medications
what does dysgeusia mean
distortion of taste function
what can cause dysgeusia
many e.g glossitis, gum infections, medications, URTI’s
what types of smells is CN 1 responsible for
common odours e.g rose, chocolate, vanilla
what types of smells is CN 10 responsible for
chemical and non chemical stimulus (protective to lungs)
