Gustation Flashcards
which papillae posses taste buds
circumvallate, fungiform and foliate
each circumvallate papillae has ______ taste buds in the ______
250 taste buds in the trench
each fungiform papillae has ____ on the ___________
3 taste buds on the apical surface
foliate papillae are organised into _______ with ____ taste buds
parallel ridges with 600 taste buds
the dorsal surface of the tongue is composed of four types of papillae
fungiform, circumvallate, foliate and filiform
circumvallate papillae get special afferent taste innervation from ____
cranial nerve IX (the glossopharyngeal nerve)
a single taste bud can contain up to ___ specialised epithelial cells (taste cells)
50
the tips of taste cells have what that increases surface area and helps concentrate chemicals onto taste receptor proteins to amplify the signal
microvilli
what are the 5 basic tastes
bitter, sour, sweet, salt, umami
what components make up a taste bud
microvilli, pore, gustatory cell, basal cell, support cell
what receptor proteins do the apical microvilli contain?
ion channels: salt & sour(acids)
GPCR: sweet, bitter & umami
what are the neurotransmitters involved?
serotonin and ATP
where do taste cells synapse onto
cranial nerves: facial VII, glossopharyngeal IX and vagus X
why can’t 25% of the population detect bitter
they have an inability to sense phenylthiocarbamide (PTC) due to a lack of T2R receptor gene
what ion channels are involved in salt sensing
amiloride-sensitive Na+ channels
what ion channels are involved in sour (acids) sensing
H+ sensitive TRP channel (PKD variant)
what receptor channels are involved in sweet and umami sensing
T1R (GPCR) - can form heterodimers
which tastes cause direct or indirect depolarisation of the taste cell
Salt and sour = direct depolarisation
Sweet, umami and bitter = indirect depolarisation
what heterodimer is responsible for sweet detection
T1R2/T1R3
what heterodimer is responsible for umami detection
T1R1/T1R3
what other receptor detects umami
metabotropic glutamate receptor 4
- taste mGlu4
what receptor is involved in bitter taste
T2Rs
specific type of alpha protein involved in bitter taste is what
alpha gustducin
what do GPCRs signal through
PLCbeta2 TRPM5 pathway
