EX3; Oral Mucosa Sensations Flashcards
What are the three parts of the dorsal tongue
root
body
terminal sulcu
Where are the root and the body of the tongue derived from
body = mucosa from branchial arch 1 root = mucosa from branchial arch 3
What kind of keratinization of the epithelium is located on the dorsal tongue
most keratinized except for in a few key locations
What kind of lamina propria does the dorsal tongue contain
flexible; other side is more rigid
True or False
The dorsal tongue does not contain a submucosa
True
The dorsal tongue contains numerous papillae, what different kinds
some papillae are taste buds
some papillae are innervated by somatosensory nerve endings
True or False
Sensation is only registered from the tongue
False; it is in the mucosa as well
What cranial nerves supply taste to the taste buds
facial - VII
glossopharyngeal - IX
vagus - X
This cranial nerve supplies the anterior mouth
trigemial - V
This cranial nerve supplies the posterior tongue and pharync
glossopharyngeal - IX
These fibers supply a touch sensation
A beta
A delta
These fibers supply a warming sensation
C fibers
These fibers supply a cooling sensation
A delta
These fibers supply a painful sensation
A delta
C fibers
This somatosensory receptor is associated with large axons (A beta) and terminates in the superficial lamina propria between the rete pegs
Meissner’s corpuscles
What kind of forces are associated with Meissner’s corpuscles
dynamic forces; rapidly adapting
This somatosensory receptor is associated with large axons (A beta) and terminus at the apices of the tete pegs
Merkel receptors
What kind of forces are associated with Merkel receptors
static forces; slowing adapting
This somatosensory receptor complexes of nerve endings and specialized epithelial cells
Merkel receptors
This somatosensory receptor complexes of nerve endings encapsulated by non-nueronal cells
Meissner’s corpuscles
What kind of threshold do both Merkel and Meissner’s receptors have
very low threshold; very sensitive
True or False
Merkel’s receptors only respond during static forces
False; they also respond during dynamic, but also (and solely) during static, Meissner’s does not respond during static
True or false
Merkel and Meissner’s receptors code painful senstations
False; they do not because their dynamic range does not extend to the noxious (harmful) range
What is used to transmit painful sensations
nociceptors
free nerve endings
A delta and C fibers
What are the main functions of the taste system
detect chemicals in the food
distinguish between nutritive/non-nutritive
detect harmful substances
What are the 5 classes of taste receptors that detect the 5 classes of stimuli
sugars (sweet) amino acids (umami) salts (salty) acids (sour) varied alkaloid, purines, glycosides (bitter)
This is goblet shaped closed of 40-60 cells at right angles to the basal lamina extending to the surface containing microvili and a taste pore
taste bud
True or False
There are no nerve fibers at the base of taste buds
False; there are primary afferent fibers at the base and some bud cells synapse with these fibers
How may taste buds are distributed in the mouth
around 8,000
Where are the taste buds located
68% on the tongue
27% on pharynx/larynx
5% on soft palate
These papillae around on the dorsal anterior tongue and contain around 1600 taste buds
fungiform papillae
Where are the fungiform papillae derived from and what are the innervated by
branchial arch 1
innervation = chorda tympani (BA2)
Where are the fungiform papillae most numerous
at the tip of the tongue; they are located there to monitor food entering the mouth
What is the shape of the fungiform papillae
mushroom shaped
Where is the keratin layer interrupted regarding fungiform papillae
at the pore and between filliform papillae
The fungiform papillae are located amongst what
filiform papillae
Where are the taste buds located on the fungiform papillae
on the dorsal surface
How many taste buds do each fungiform papillae typically have
around 3
These are heavily keratinized spine shaped papillae which do not contain taste buds
filiform papillae
What are filiform papillae innervated by
somatosensory fibers
These are 2-9 parallel folds, dorsoventral orientation on the lateral aspect of the most posterior anterior tongue; strategic location to monitor food during chewing
foliate papillae
How many taste buds are located on the foliate papillae and what are they innervated by
around 1300 taste buds
innervated by glossopharyngeal (BA3)
Where are the taste buds of the foliate papillae and circumvallate papillae located
in the trenches; not on the surfaces
What are the foliate papillae and circumvallate papillae closely associated with
salivary glands
specifically Von Ebner glands
These are 8-10 papillae arranged in a “V” on the most posterior anterior tongue with a central connective tissue core surrounded by a trench used to monitor food just before swallowing
circumvallate papillae
How many taste buds are on the circumvallate papillae
around 2400; densely packed
Though the different taste papillae are distinctively histologically and innervated by different nerves, they are generally functionally redundant in their ability to do what
sense different tastes
The taste buds on the larynx (epiglottis) respond to deviations in this, indicated the signal to protect the airway
isotonicity; response to water
True or False
A single fungiform papillae can only detect one specific taste
False; they can usually detect more than one quality (~3 buds/papillae)
What is important to know about the functional redundancy of the taste system
it makes it resilient to the face of partial taste loss
When the chorda tympani is numbed, which side are the taste stimuli undetectable
on the ipsilateral side to the anesthesia
What occurred involving the taste when both of the chord tympani’s were numbed
there was no obvious taste loss
True or False
The number of taste papillae varies greatly between individuals
True; women tend to have more then men
True or False
The number of taste papillae dramatically decreases with age
False; it may only decrease slightly but mainly due to lost of olfactory sensations
Fox accidentally discovered marked individual differences in the ability to taste what and the bimodal distribution of thresholds indicated this
bitter phenylthiocarbamide (PTC) it is an inherited trait
In the last how many years was the functional characterization of receptors understood
in the last 15 years
2000-2009
This is a 30 member family of G-protein coupled bitter receptors of which each has a limited range for bitter compounds
tas2r
What is largely responsible for the sensitivity differences to bitterness (PTC) in tas2r receptors
amino acid substitutions
Vegetables containing this compound are significantly more bitter to people who are homozygous for PTC sensitive tas2r
glucosinolates
True or False
People with more sweet receptors prefer lesser sweet things
True;
people with less sweet receptors prefer more sweet things, this can contribute to caries production
True or False
both genetic and environmental factors contribute to individual taste sensitivity and preference
True
These cells of a taste bud are on the lateral aspect, in the epithelium at right angles to the basal lamina, contain microvili, and do not synapse
perigemmal cells
What is the presumed function of perigemmal cells
support or renewal
These cells are located at the base of the taste bud, in the epithelial basal cells, and their function is renewal
basal cells
These cells are at the center of the taste bud and have receptors that convey stimulus
elongated cells
This type of elongated cell stains for glial markers suggesting a supportive role; it also may respond to salts, and there are no synapses
Type 1 (dark)
This type of elongated cell expresses receptors for taste substances and responds to taste stimuli; there are two types
light cells
This type of light cell responds to sour taste and synapses with primary afferent nerves
Type III
This type of light cell responds to bitter, sweet, and amino acid tastes and does not synapse with primary afferent nerves
type II
Type II and type III use this to communicate with the primary afferent taste nerves; in regards to type II, it is the primary transmitter
ATP
K19 (keratin) is expressed during what, and this indicates what
expressed during development and reflects the rapid turnover of taste receptor cells
In which embryological week does the taste buds first appear
week 8
In which embryological week does the taste pores first appear
week 12
What has been indicated about taste preferences in infants
the basic taste system is hard wired at birth (facial expressions upon bitter/sweet) but the natural taste preferences are altered by experience (enfamil and nutramigen formulas)