ex3 oral mucosa2

Question 1

is the dorsum of the tongue considered to be specialized tissue

Answer 1

Yes. the dorsum of the tongue = specialized tissue.

obvious, but sets tone//
- dorsum = the superior surface of the tongue.(has all the papilla) . from branchial arch 1, while the root is BA3.. so, different things fused.

Question 2

is the epithelium of the dorsum of tongue keratinized or non-keratinized?

Answer 2

the epithelium of the tongue (by defnintion means the surface layer) is Mostly Keratinized. a few Imp. location are non-keratinized.

recall: keratinized = no nucleus,

Question 3

a wiki fact:
Irregularities in the connective tissue surface, such as papillae found in the tongue, increase the area of contact of the lamina propria and the epithelium.[

Answer 3

true

Question 4

what cranial nerves contribute to innervation of the tongue?

Answer 4

CN 7,9,10 contribute to innervation of the tongue. the tongue is Densely innervarted by a Variety of sensations
touch
temperature
pain

(Abeta, Adelta, and C-fibers all invovled
touch = Abeta
temp:: Warm = C fibers, Cooling = Adelta
Pain = C fibers and Adelta

Question 5

what sensations are C fibers carryng in the tongue?

Answer 5

C fibers carry Pain sensation as well as WARMING in the tongue.

A delta fibers sense the cooling aspect of temperature, as ell as pain along w c fibers

Question 6

what does CN 5 innervate in the tongue>

Answer 6

CN5 innervates afferent sensation of the ANTERior 1/3 of the tongue ( via its lingual branch).

• • CN7 has the chorda tympani that supplies afferents for TASTE special sense in ANT 1/3 of tongue
• • posterior 2/3 of tongue, both sensation and taste are innervated by CN9, the glossopharyngeal nerve.
• • Nearly all of the motor nerves of the tongue are via the hypoglossus nerve, CN12

further:wiki:The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for sensation in the face and certain motor functions such as biting and chewing.

Question 7

What two specialized mechonoreceptors are found in the oral mucous membrane of the tongue?

Answer 7

Meissner’s corpusles and Merkel’s endings are found in the tongue. these are also found elsewhere (recall.. fingers, etc)

Meissner’s corpusles = sensitive to the tiniest of changes (in body, detects flutters = rapid, tiny changes) but insenstive to a constant (unchaging) sensation
Merkel’s ending = slow adapting, . senses the change, but then maintains sensation of a continueou, unchanging stimulation . (in the body= senses pressure, textures..)

Question 8

Do Meissner’s corpuscles enter the epithelium?

Answer 8

Usually no. Meissner’s corpuscles do not enter the peithleium, though they Do extend to the superficial lamina propria(the layer just beneath/adj to the epi. .. so, Meissner’s get Really close to the epi.) and they terminate bt the Rete Pegs (recall- rete pegs = interface bt lamina p and epithelium)

Meissner’s function to detect rapid, flutter-fast sensations = fast adapting. do not detect maintained/unchaigng sensation, but detect the start of it

Question 9

Are Schwann cells associated with Meissner’s corpuscels of Merke;’s nerve endings?

Answer 9

Schwann cells are protective,cushioning, and associate with the Meissner corpuscle.. tucked into the M. ‘s helical structure

Question 10

What type of nerve fibers make up Meissn’ers corpuscles? what about merke;’s nerve endings?

Answer 10

Abeta and Adelta make up the fibers of both Meissn’ers and Merkels mechanoreceptors.

Question 11

Where do Merkel’s nerve endings terminate?

Answer 11

Merkel’s nerve endings terminate in the apex (apices) of the rete pegs, also within the lamina propria ((check if LP correctl..) .. the Merkel cells enfold the nerve endings which are ‘slow-adapting) ((vs Meissner’s = fast=adapting

Question 12

Do Meissner’s or Merkel’s .. detect pain?

Answer 12

No. Neither Meissner’s nor Merkel’s nerve endings are able to detect pain. Painis dtected by NOCICEPTORS that only detect pain. cmposed of C and Adelta fibers.

• nociceptors have free nerve endings and extend in the lamna propria as well as the epithelium

Question 13

in what tissue layer(s) are taste buds located?

Answer 13

Tastebuds sit in the epithelial layer.. the basal cells of the taste bud sit on what would be the basal lamina (except, cells are keratinized.. _ and the microvilli of the taste buds extend through the micropore opening of the keratin of the surface epithelium

Question 14

do Abeta fibers extend into the peithelium?

Answer 14

No. Abeta fibers stay in the lamina propria . Abeta fibers are assoc (as well as Adelta) with Merkels nerve endings and Meissner’s corpuscles .. and these are confined to the lamina propria

Question 15

what is umami””? u

Answer 15

umami is the flavor that describes amino acids = protein

Question 16

what is the flavor of acids?

Answer 16

Acids have an acidic flavor = Sour

Question 17

name the 4 types of papillae that cover the tongue

Answer 17

there are kinds of papillae that cover the dorsum of the tongue ,these are the

• fungiform papillae (have avg 3 taste buds- concentrated at tip of tongue)
• foliate papillae (have taste buds in trenches, located laterally along tongue root)
• circumvallate papillae – about 10 of these, there tastebuds located in encircling trenches.. located at terminal sulcus (signal posterior tongue)
• • lastly, filiform papillae = have NO tastebuds!! ((only papillae of tongue wo tastebuds!) .. but have somatosensory– so sense everythig except taste - sense touch, temperature, pain, proprioception

Question 18

apprx how many aste buds are on the tongue?

Answer 18

approximtely 8000 tastebuds (8k) are on the tongue. the taste buds are almost evenly divided bt the papillae containg tastebuds – the fungiform, foliate, and circumvallate.. however, of the 3 types, the circumvallate papillae generally have more tastebuds than the other 2 types

Question 19

where is the foliate papillae located? function?

Answer 19

The foliate papilla are located dorsoventrally in parallel folds along the root of the tongue (poster to the molars).. these folds contain tastebuds, that are in good location to snese food during chewing .

• the tastebuds are located int eh trenchies of the folds, the glossopharyngeal nerves = sensory and taste innervation ((characteristic of postr 1/3 of tongue)
• foliate tastebuds closely assoc with von ebsner glands = salivary gland

Question 20

circumvallate papillae are located on the most poster part of the anterior tongue (just prior the terminal sulcus that demarcates the posterior tongue_.. what role do these paillae have

Answer 20

there are about 8-10 cv papillae arrnaged in a “V” formation demarkating the end of the naterior tongue.. the cv papillae contain the majority of tastebuds on teh tongue, and these tastebuds are inside the trneches that enrcilr the papillae. the papillae/ tastebuds monitor the food as it is being swallowed. durring agluttination (swallong) he tongue presses up to the palate.. this action squishes food into the CV trenches which stimulates the entrenched taste buds

Question 21

what types of tastebuds are associated w Von Ebner’s saliary glands?

Answer 21

both foliate and CV tastebuds are closely associated w von ebner’s salivary glands

Question 22

Describe Von Ebner’s salovary glands

Answer 22

from wiki:Ebner’s glands, also Von Ebner’s glands are exocrine glands found in the mouth. More specifically, they are serous salivary glands which reside adjacent to the moats surrounding the circumvallate and foliate papillae in the posterior one-third of the tongue, anterior to the terminal sulcus.

on Ebner’s glands secrete lingual lipase,[1] beginning the process of lipid hydrolysis in the mouth. These glands empty their serous secretion into the base of the moats around the foliate and circumvallate papillae. This secretion presumably flushes material from the moat to enable the taste buds to respond rapidly to changing stimuli.

Von Ebner’s glands are innervated by cranial nerve IX, the glossopharyngeal nerve

Question 23

True/False Certain regions of the tongue only detect a certain type of flavor

Answer 23

False. The tastebuds of the mouth are redundant in falvor sensation– while some regions have more intense detection of the flavor, no region only detects only one flavor. The tongue detects all flavors all over. ** one excetion, the tastebuds of the larynx detect differences in isotonicity (ex, diff bt saliva and water)

Question 24

can a single fungiform pappillae detect more than one flavor?

Answer 24

usuall, yes! a single fungiform papillae (recall, has avg 3 tastebuds) can detect more than one flavor quality.

– further each indiv tastebud is made up of elongated cells of which there are 3 types. types 2 and 3 detect different flavor qualities and can be located side-by-side in the same taste bud

Question 25

T/F if the chorda tympani on one side of the head is damamged, a signifcant loss in taste sensation is perceived.

Answer 25

False. even if the chorda tympani of half the tongue is blocked ( so half of the anterior 2/3 tongue w/o aste innervtion).. there isnt a big loss of taste peception.. the functioning tastebuds register just as much as if all the tastebuds were active. this is important in that taste sense is resiliant to total loss

Question 26

Is the loss of taste with age attributed only to the decrease in number of tastebuds?

Answer 26

No. Recall the studies that show that even if half the tastebuds were nonreceptive (such as by chorda tympani damage ipsilaterally).. the body still senses nearly all the same amt of flavor quality info, While the sense of taste declines with age. Stdies show that the number of tastebuds decline with increasing age.. even more contributing, is the bigger decline of olfaction sense.. the decline of olfaction contributes even more to the decline of taste.

Question 27

What is the sig. of PTC?

Answer 27

PTC is a bitter tasting compound that only some ppl taste – this is due to genetics. Demonstrated that some ppl have difrences in taste receptors that account for their perception of flavor (and even impacts their eating habits).

• 1) tas2r is in the bitter family, and detects the bitter compoiund found in cruciferous veggies (simmilar to PTC) that ppl with PTC gene dislike… as such eat less veggies
  2) some ppl with more sweet receptors.. therefore prefer/satisfied by things with less sweets (vs someone w low number of receptors, prefers very sweet food choices)

Question 28

What is different about bitter receptors from sweet receptos (generally)

Answer 28

The main difference bt bitter and sweet receptors is range of taste. Bitter receptors are more specialized and detect a limited range of bitter compounds ((logical, bitter = often toxic compounds.. a warning and distinguishes type of bitter) vs. sweet – sweet receptors detect a much larger range of sweets (so fewer receptor types exist)) also logical bc sweet recognized by body as a nutrient for energy (so less discerning)

the bitter receptors - include tas2r (boroccoli bitterness example).. there are 30 membrers in this family (a lot!) and they are Gcoupled receptors (signal transduction)

Question 29

what are the 3 main types of cells in a taste bud?

Answer 29

the 3 main types of cells in a taste bud are the perigemmal cells, basal cells, and elongated cells.

perigemmal = no microvilli, same orientation as elongated cells (perpendicular to epithelial basal lamina area) = likely supportive funciton

basal cells == at the basal lamina area border of the taste bud = imp for renewal ((taste bud cells HIGHLY replenished.. think, caustic enviro))

elongatd cells = the functional cells. 3 types. type 1 = dark staining and is functional (glial characteristics)
types 2 and 3 = light staining and TASTE RECEPTOS
—type 2 = bitter, sweet , amino acids . no primary afferent
—type 3 = sour – synapses with primary afferent nerve

Question 30

Type 2 elongated cells of the taste bud do not have primary afferent synapses… how do they communcate?

Answer 30

Type 2 elongated cells of the taste budsa = are taste receptors imp for reception of bitter, sweet, and amino acid qualities.. they do Not have a synapse w primary afferent.. but communicate via ATP.

type 3 do have a priamry afferent synapse, but also able to communicate hte same way w ATP.

ATP used w g-coupled prtn receptor.. uses a unqiue channel for singalling

Question 31

T/F like other epithelia, differently located taste buds are able to express different keratins

Answer 31

True. like other epithelia (inc oral eptihelia) the tatebuds in different locations produce different keratins
== keratins == . Keratin monomers assemble into bundles to form intermediate filaments, which are tough and insoluble and form strong unmineralized tissues ..

so differnt intermediate filaments expressed in differnet places on the tongue

Question 32

When does the tongue first start to appear in development?

Answer 32

The tongue first starts to appear in week 4 IU in utero. the first taste buds appear IU week8, and the first pores appear in IUweek12. == so the taste system is functional at birth

Question 33

T/F early exposure to flavors impacts ‘liking’ of a flavor

Answer 33

Early exposure - and the duration of exposure early on can impact how the indiv percieves the flavor - as in if they like the flavor or not. early exposure + duration could render the indivdual to like a flavor that is otherwise considered unsavory.

also, a bad experience (during life) can turn a person off to a certain flavor