specialized mucosa and taste Flashcards
body mucosa of the tongue
BA1
root mucsoa of the tongue
BA3
keratinization of tongue mucosa
Eptilium mostly keratinzied except for key locations
lamina propria of tongue
flexible
submucosa of tongue
No submucosa
surface of tongue
Numerous papillae with a rough surface
what are the papillae of the tongue
some Taste buds
otheres inneratved by somatosensory nerve ending
is sensation confined to the tongue
No
separates the root from the body of the tongue
TErmainal sulcus
fibers for touch for oral mucosa
Ab and A delta fibers
fibers for warm of oral mucosa
C fibers
fibers for cooling of oral mucosa
A delta
fibers for pain of oral mucosa
A delta and C fibers
Cranial nerve for sensation of anterior mouth
CN V
Cranial nerve for senstion of posterior tongue and pharynx
CN IX
taste bud cranial nerves
CN VII, IX, X
what makes up Flavor
Taste
Olfactory
Oral Somatosensory (temp, texture, spice)
what parts of flavor are well fused
taste and olfactory components
how is the olfactory epithlium stimulated
volatile molecules from food stimulated the olfactory epithium via orthonasal and retronasal
what part of olfaction is very important for food flavor
Retronasal (through the back of the mouth/pharynx)
do taste and olfactory senses use the same never
No use separate cranial nerves
where do Taste and Olfaction interact
extesnively in the CNS especailly the primary qustatory corte (insula)
Hypergeusia
Heightened sensastion of taste (V. rare)
Hypogeusia
Reduced sensastion of taste
Ageusia
No sensation of taste (V. rare)
parageusia
Incorrect taste sensation
Dysgeusia
change in taste quality
phantogeusia
taste in the absence of stimulus
How often do people self report problems with taste or flavor
about 18% most think they have taste flavor loss at age 25
what part of sensing flavor is common
Olfactory deficits are more common than Hypo or Ageusia (less common)
alfactory alone most
then olfactory and taste
taste alone
what are the greatest causes of taste loss
Idiopathic (unknown) Post-traumatic (after injury) Post-operative (after surgery) post-infection medical disease/cause Chemical but most are unknown cause of taste loss
function of the taste system
Detect chemicals in food
why is taste important
distinuish nutrients and non-nutritive substance
distinguish different nutrients
detects harmful substances - poison, caustic chem
classse of taste receptors detect
detect different classes of stimuli
different quality that we can taste
sugars (sweet) amino acid (umami) salts (salty) acids (sour) varied, alkaloids, purine base, glycosides (bitter)
what does the sensation of spiciness come from
NOT taste but pain (TRP receptors)
recetpor for chilis
TRPV1
Receptors for garlic
TRPA1
what makes up a taste bud
a goblet shapped cluster of 40-60 cells
Orientation of taste bud
TAste pore opens up into a lummer with nerve fibers comming out the other size
where does the taste bud extend from
BAsal lamina to the surface
where is the location of taste recetpors
Microvilli of the cells
the opeing to the lumen to the thetaste bud
Taste pore
where are the afferents of the taste bud
Primary afferent fibers at base where bud cells make synapses with these fibers
number of taste buds
8000
where are taste buds located
68% on tongue
27% on pharynx and larynx
5% on soft palate
what lingual papillae are taste buds associated with
foliate papillae (side of tonue)
Circumvallate ( big ones on the connection between root and body of tongue)
Fungiform papilla
where are fungiform papillae
on the dorasl anterior of tongue (BA1)
what innervates the fungiform papilae
by chorda tympani brnach of VII (BA2)
taste bud bumber of fungiform papilllae
1600
where are most fungiform papillae found
at the tip, strategically located to monitor food entering mouth
shape of fungiform apillae
mushroom-shpaed
where are fungiform papillae found
located amoung more numerous filiform papillae
taste buds on filiform papillae
No
where is keratin layer interrupted on fungiform papillae
Interrupted at the pore
how is keratin between papilla
reduced
where are taste buds located on the fungiform papillae
located on the dorsal surface of fungis
do single sections of fungiform papillae have multiple taste buds
NO, may have none of 1
most have fungis have how many taste buds
ave of 3
where are taste buds on fungi
Dorsal not on the side
shape of filiform papillae
spine shape
keratin of filiform papillae
heavy keratinized
taste buds of filiform papillae
Do not continue buds
what does Filiform papillae innervate
only by somatosensory fibers
how are foliate papillae organized
2-6 parallel folds in dorsoventral orientation
taste buds of foliate papillae
1300 taste buds densely packed
what innervates foliate papillae
glossopharyngeal (IX, BA3)
location of foliate papillae
lateral aspects of most posterio anteriotongue (post to molar, anterior to CVs)
roll of Foliate papillae
strategic location for monitor food during chewing
location of taste buds in foliate papillae
in the trenches not on the surface
what do foliate taste buds associate with
with salivary glands (Von Ebner)
number of circumvallate papilae
8-10
taste buds of circumvallate papillae
2400 buds (densy packed)
what makes up the circumvallate papilae
central connective tissue core surrounded by a trench
where are circumvallate papillae
arrranged in a v on the most posterior AT
roll of circumvallate papillae
Monitor food just before swallowing
where are circumvallate papilae located
In trench, not dorsal surface
what innervates circumvallate papillae
Innervates by glossopharyngeal N
what do buds of Circumvalate associate with
Von ebner’s glands
are taste buds functionall redundat in their ability to sense different taste
yes
what taste buds are not functionall redudant
taste buds on the larynx (mainly respond to deviations from isotonicity, to protect the airway)
how are regional differences in taste buds
relative but not absolute
do fungiform papillae detect 1 quality
No, detect more than 1 quality
what does the functional redudancy of the taste system do
makes it resilient in the face of partial taste loss
is taste ipsilateral or contralateral to chorda tympani anesthesia
taste stimuli become undetectable on the side of the tongue ipsilateral to anesthesia
after bilateral choda tympania anesthsia if you give taste to the whole mouth
produces minimal efects on whole mouth perception
what happens to whole mouth taste due to CT/lingual nerve damage caused by 3rd molar surgery or CT damage by middle ear surgery
negligible effect on whole mouth taste
damage or anesthesia of a single taste nerve results in what with specific spatial test
can clearly detect the perceptual effects of damage
effect of damage to a single nerve when using the whole mouth
Little effect
why is there little effect when you are missing a nerve, but use the whole
functional redundanc and ability of the CNS to somehow compensate for partial loss
study depth at taste bud removal
perceptual tests used to assess these effects are crude
effects of glossopharyngeal damage studied minimally
do all people have about the same amount of taste papillae
varies greatly between individuals
how does taste papillae change with age
slighly declines but only slightly (feeling of taste loss comes from decline in olfaction)
what can affect fewer taste papillae
Genetics
smoking
alcohol
functional consequences of few taste buds
Not adequately studied
other types of individual variability in the bio of taste system are related to
Differences in taste preception (the ability to taste specific classes of moelcules or qualities
what is a substance that individualls taste differently
bitter phenylthiocarbamide (PTC)
how does one taste bitter phenylthiocarbamide
bimodal distribution of thresholds (inherityed)
the critical features of the molecular strucutre of PTC
thiourea moity
what is the receptor for bitter
tas2r
family size of bitter taste recetpor
30 member
what kind of receptor is better taste
G-protein coupled
what does tas2r detect
a limited range of bitter comploudns
the receptor for PTC
tas2r38
what dtermines sensitivity to bitter taste
substitution of 2/333 amino acids
what are tha alanin and valine positions for taste intesnity imporance vs proline and alanine
49 and 262
people that are homogenous for PTC sensitive form of tas2r taste what else as bitter
mustard greens
turnips
broccoli
why would someone who is pTC sensitive also dislike some veggies
these vegies contain glucosinolates which also has a thiourea moitey
bitter sensitivity also applies to what
to some artificial sweeters since they use the same Tas2R receptor class
what else besides bitter taste is controlled by genetics
receptors for sweet stimuli
how is the sweet receptor differences occur
differences in the promoter region determine the number of copies of the sweet receptor ( controls intensity of the sweetness)
difference in amount of sweet receptors leads to
differences in the most preferred sugar concentration
what other factors control taste sensitivity
Genetic and encirnonmental(not completely understood)
how do taste buds look at the light microscopic level using standard stains
rather homogeneous
are all taste buds the same
Multiple types of taste bud cells
Dark taste bud cell type
Type I
staining for glial markers shows that type I cells do what
are supportive due to lack of microvilli and synapses
but may also respond to salts (unclear)
light staining taste bud cell type
Light cells
morphology of light cells
microvilli that reach the taste pore
what do light cells do
express receptors for tasting stimuli
what do type III cells do
taste sour
types of light cells
Type III
Type II
what do type III cells synapse with
synapse with primary afferent nerve
what do type II cells do
taste bitter, sweet, and amino acids
do type II cells synapse with primary afferent nerve
no
how to distinguish type II and III cells
due to expression of specific proteins
how do Type II and Type II cell communicate with the primary afferent taste nerves
use ATP
what kind of cynapse does a Type III cell use
classic synapses
how is ARP relased from Type II cells
without the aid of a typical synapse using a specifial voltaged gated ion channel
what voltage gated channel allows for the relaese of ATP from Type II cells
CALHM1 (calcium homeostasis modulator 1)
what are taste buds made of
Modified epithelial cells
what do taste buds do similar to epithelial cells
continually replaced
where do new taste bud cells come from
basal cells (also perigemmal cells) just outside the taste bud to give rise to a post-mitotic taste bud
what do the post mitottic taste bud precursor cells express
Sonic headgehod
what do sonic hedge hog taste bud precursors give rise to
all 3 types of cells in the taste bud (I, II, III)
what does sonic hedge hog due in the taste bud
released from the precursor cells and acts on surrounding cells to maintain taste buds
what does the taste bud develop from
specialized epithelium called the placode (similar to that of the tooth)
what is needed for taste bud development
cell-cell signalling
final differentiation requires neural innervation
similariteis between tooth buds and taste bud development
use same moelcules (and used also in many different organs)
important pathways for taste bud and tooth
Wnt/beta-catenin
BMP
SHH
FGF
do the same molecules always have the same effect on the taste bud developemt
same molecules can have a different effect at a different time
when the tongue appears
week4
when the lingual papillae develops
week 8
when the taste buds first appear
week 8
when taste pore first appear
week 12
How early does taste develop
early and is at least partially competent at birth
how do we know babys can taste
give them bitter stuff and sweet stuff to see a reaction
effect of experience and taste
natural taste preference can be altered by experience
study do to the effect of early experience on preferences of 2 formulas
early preferences to certain formulas
