oral cavity

Question 1

what is the function of teeth?

Answer 1

to survive cyclical loading

Question 2

what are the two regions of the oral cavity?

Answer 2

vestibule

oral cavity proper

Question 3

what is the vestibule?

Answer 3

the 3D space outside the teeth

Question 4

what is the oral cavity proper?

Answer 4

the 3D space inside the teeth i.e. where your tongue lives

Question 5

what is the superior border (roof) of the oral cavity?

Answer 5

hard and soft palate

Question 6

what is the posterior border of the oral cavity?

Answer 6

oropharyngeal isthmus

Question 7

what is the anterior border of the oral cavity?

Answer 7

the lips

Question 8

what is the lateral border of the oral cavity?

Answer 8

the cheeks

Question 9

what is the inferior border of the oral cavity?

Answer 9

mucous membrane covering mylohyoid muscle, mostly occupied by the tongue

Question 10

T/F the oral mucosa lacks hair follicles and sweat glands, with few sebaceous glands?

Answer 10

True

Question 11

what type of epithelium is the oral mucosa?

Answer 11

• stratified squamous, both keratinized (ortho & para) and non-keratinized
• derived from the ectoderm like skin
• renewed every 1-2 weeks

Question 12

characteristics of the lamina propria of oral mucosa

Answer 12

rete pegs, which hold epithelium to underlying lamina propria

• contains manly lymphocytes in loose aggregates, as well as tonsils (3x10^9 PMNs daily)
• contains small mixed sero/mucous salivary glands

Question 13

what is the difference between the rete pegs in the lining mucosa vs. masticatory mucosa?

Answer 13

lining: flatter, rounded rete pegs
masticatory: sharper, more pronounced rete pegs

Question 14

what are the 3 main divisions of the oral mucosa?

Answer 14

lining mucosa: non-keratinized
masticatory mucosa-keratinized
specialized mucosa- taste buds

Question 15

where is lining mucosa found in the oral cavity?

Answer 15

cheeks
inside of lips
floor of mouth
ventral tongue
soft palate
alveolar mucosa

Question 16

where is the masticatory mucosa found?

Answer 16

gingiva( attached)
parts of the dorsum of the tongue
hard palate

Question 17

where is specialized mucosa found?

Answer 17

dorsal and lateral surfaces of the tongue

Question 18

what is the difference between general oral mucosa and oral mucoperiosteum?

Answer 18

-general: has a submucosa, may or may not attach to bone, gerally lining mucosa
-mucoperiosteum: medial hard palate, attached gingiva, no submucosa, robust lamina propria (lots of collagen)
attaches directly to bone

Question 19

what is the difference between ortho and para keratinized?

Answer 19

ortho: no nuclei visible in keratine
para: some, sad, lonely looking nuclei retained in keratin layer
NB: the difference is rarely totally clear cut and they can transition back and forth

Question 20

stratum corneum

Answer 20

anucleate then acelluar layer of squames of cross-linked keratin coated with lipid

Question 21

stratum granulosum

Answer 21

keratohyalin granules: keratin aggregation

lamellar granules: lipid coating

Question 22

stratum spinosum (prickle)

Answer 22

desmosomes

Question 23

stratum basale

Answer 23

stem cells

hemidesmosomes

Question 24

what layer of cells does non keratinized epithelium not have?

Answer 24

stratum corneum or stratum granulosum

Question 25

lining mucosa

Answer 25

- non keratinized | - lacks stratum granulosum (thus lacks keratinhyaline granules)

Question 26

soft palate

Answer 26

lining mucosa glandular tissue separates oral and nasal cavities one side will have respiratory epithelium

Question 27

hard palate

Answer 27

masticatory epithelium: keratinized stratified squamous ortho and/or para - junction between epithelium and underlying CT is interdigitated with many elongated papillae - Lamina propria often binds directly to underlying bone - may see some glandular tissue

Question 28

gingiva

Answer 28

attached: firmly bound to bone around roots of teeth, stippled due to rete pegs - free or marginal: lies unattached around cervical region of teeth - interdental: part between teeth

Question 29

what is the mucogingival line

Answer 29

delineates the attached gingiva from alveolar mucosa. Transition between masticatory and lining mucosa

Question 30

mucogingival junction epithelial changes and others

Answer 30

-epithelial: attached gingiva is keratinized alveolar mucosa: non-keratinized -other: attached gingiva-dense lamina propria, many collagen bundles, attached to bone alveolar muscosa: lamina propria is looser with many elastic fibers, which give the mucosa elasticity

Question 31

lips

Answer 31

- keratinized skin - vermillion zone(thin keratinized SS epi w/ lots of superficial capillaries) - mucocutaneous junction or intermediate zone we transition to labial mucosa - intermediate zone is parakeratinized - labial mucosa: non keratinized, thick, flexible, smooth interface with CT

Question 32

cell types of the oral mucosa

Answer 32

90% keratinocytes other 10% are: -langerhans cells in stratum spinosum -merkel cells-touch receptors which synapse with sensory nerves -melanocytes: produce melanin, provide pigmentation

Question 33

filiform papillae

Answer 33

``` keratinized epi most nemerous ant. 2/3 of tongue gives grip via friction to tongue no taste buds ```

Question 34

fungiform papillae

Answer 34

non keratinized epi anterior part of tongue/mostly the tip mushroom like and larger than filiform taste buds on upper surface

Question 35

foliate papillae

Answer 35

non keratinized epi less pronounced in adult humans sides of tongue contain taste buds on the sides in the crypts

Question 36

circumvallate

Answer 36

``` keratinized epi posterior part of tongue massive circular looking things only 10-12 contains taste buds in crypts **Von Ebner's glands (serous salivary glands) wash out crypts ```

Question 37

taste buds

Answer 37

barrel shaped structure, composed of chemoreceptive spindle cells - apical ends all terminate just below surface in the taste pit - taste pit communicates with surface through taste pore - taste comes from binding different receptors, which trigger various signaling cascades - NO distinct regions for different tastes

Question 38

what important things does saliva do?

Answer 38

lubricates the mouth-mucosa secretion buffering-bicarb, phosphate ions digestion-amylase protection: washing action for bacteria and sugar, lactoferrin, lysozyme and defensins, IgAs

Question 39

parotid glands

Answer 39

``` -quite large/lagest 25% of volume -mostly serous secretions -secrets alpha amylase -particularly contributes during active salivation ```

Question 40

submandibular glands

Answer 40

mixed secretions, MOSTLY serous, but some mucous 60-67% of volume -mucous-mucin -big contribution of passive 'background' salivary volume

Question 41

sublingual glands

Answer 41

mixed secretions, but really mostly mucous 3-5% of volume smallest mucous capped with serous demilunes

Question 42

staining difference between serous and mucous cells

Answer 42

serous: stain dark, more protien content mucous: stain lighter

Question 43

salivary glands

Answer 43

saliva is deposited at one end, flows through the duct system, modified at various points and is pushed out into the oral cavity - myoepithelial cells mixed with secretory cells contract and push saliva out - end product is hypotonic

Question 44

salivary secretion intercalated ducts striated ducts

Answer 44

- first into intercalated ducts and then onto straited ducts - intercalated ducts have thin, simple cuboidal epithelium - striated ducts: simple columnar epithelium, modify saliva by secreting bicarb and absorbing Na and Cl - collectively these are known as intralobular ducts because they collect saliva from lobules of same lobe

Question 45

interlobular ducts

Answer 45

larger than intralobar ducts, and collect saliva from multiple lobes - stratified columnar - lead to excretory ducts where saliva is excreted in oral cavity

Question 46

interclated duct

Answer 46

mostly a conduit, simple cuboidal epithelium

Question 47

striated duct

Answer 47

large lumen, light even staining columnar cells, central nuclei

Question 48

path of saliva

Answer 48

interclated ->striated-> interlobar->excretory ducts-> oral cavity ** inteclated and striated are know as intralobar ducts