oral mucosa

Question 1

What is the oral mucosa

Answer 1

-membrane that covers entirety of oral cavity
-vast tissue
-upper lip, lower lip, gums, floor of mouth, tongue, hard palate, cheeks

Question 2

The Functions of the Oral Mucosa

Answer 2

o Protection – against mechanical (due to mastication), abrasive and microbial threats (saliva all the time)
o Sensation (neuroreceptors embedded under mucosa)–touch, temperature, taste, thirst and pain
o Secretion – minor salivary glands and limited sebaceous glands
o Absorption – sublingual (applied under tongue) dissolving drugs
o (Thermal regulation – only in animals e.g. when panting, not humans)

Question 3

difference between oral mucosa and skin

Answer 3

1. colour-oral mucosa lighter
2. moisture- oral mucosa has constantly moist surface due to secretion of saliva
   3.appendages- oral mucosa doesn’t have skin appendages such as hair follicles and sweat glands

Question 4

types of oral mucosa

Answer 4

1. masticatory (keratinised)
2. lining
   3.specialised (keratinised)

Question 5

masticatory

Answer 5

-keratinised
In gingiva (gums) and hard palate
-has extra protective layer called keratin which helps protect mucous membrane and underlying structures from masticatory forces

Question 6

lining mucosa

Answer 6

non kartinised
Lip (labial), cheek (buccal), floor of mouth, under surface of tongue
-not keratinised as not subject to masticatory forces

Question 7

specialised oral mucosa

Answer 7

keratinised
Surface of tongue,
-anterior 2/3 has specialised mucosa (has structures called tongue papillae, some which have taste buds), keratinised due to mastication forces
-posterior 1/3 covered with oral mucosa and full of lymphoid tissue-called keratinised

Question 8

tissue components of oral mucosa

Answer 8

1. Covering epithelial tissue
   
   2. Supportive lamina propria (connective tissue)
      Submucosa (absent at certain sites)

Question 9

What are epithelial tissues

Answer 9

Closely packed layers of cells that cover surface of body/line cavity of body

Question 10

types of epithelial tissue

Answer 10

Simple (one layer)
Stratified (2 layers)

Question 11

types of attachment between epithelial cells

Answer 11

-hemidesmosome
-gap junction
-desmosome (thickening of cell membrane on each side of cell)
-adherens junction (transmembrane protein)
-tight juction
look at pic

Question 12

What is oral epithelium made of

Answer 12

-Oral epithelium made of stratified squamous (flat) epithelium
-2 types keratinised (gum/palate)/non-keratinised (cheek)

Question 13

What are keratinocytes?

Answer 13

-found in outermost layer
cells of keratinised epithelium, Cells that form majority of epithilium coverage of oral mucosa, have cytokeratin in them and they form keratin

Question 14

Non keratinocytes:

Answer 14

Cells of the non-keratinised epithelium,Fewer in number, have specialised function, don’t have cytokeratin/synthesise keratin

Question 15

What is difference between keratinised and non keratinised tissue?

Answer 15

Non keratinised cells are thicker and have more layers

Question 16

Keratinised:
Basal layer

Answer 16

Smaller size on for non keratinised
-mainly cuboidal
-basal layer made up of stem cells (do mitosis and cell division as they generate all layers of epithelium

Question 17

keratinised Prickle cell layer:

Answer 17

shrink and desmosomes more apparent so appears prickly
-in keratinised=bundles of tonofilaments and tonofibrils, in non-keratinised only dispersed tonofibrils

Question 18

keratinised Granular cell layer

Answer 18

in keratinise, as contains more tonofibirls, contains granules that hold the hyaline keratin in it

Question 19

Keratinised surface layer

Answer 19

Cells filled with keratin, organelles start shrinking till cell completely keratinised and lose all organelles, become dead and part of keratin layer

Question 20

Non keratinised layers

Answer 20

-after prickle cell layer, there is intermediate layer as not granular, no granules of keratin but have membrane coated bodes, have glycogen in them
Surface layer-as they mature, have less organelles but retain cell nucleus and some cell organs

Question 21

non keratinocytes

Answer 21

1. langerhans: immune/defence: antigen presenting
2. melanocyte: pigmentation: synthesis of melanin. More active in ppl with darker skin, melanin secreted within epithelia to give palate darker colour
3. Merkel: sensory: tactile sensation- touch stimulus felt here

Question 22

structure of lamina proprietary

Answer 22

-Supportive connective tissue made of connective tissue
-lose connective tissue forms papillary layer under epithelium
-interlinked with superficial rete pegs
-papillary layer on top, reticular layer on bottom
-full of fibres

Question 23

What is basal lamina

Answer 23

-Interface between lamina propria and epithelial tissue
-Connect cells to each other, hemidesmosomes are half desmosomes connect basement membrane (membrane that basal cells sit on) to lamina propria. This is on lamina lucida (transparent area)
-layer under is lamina dense-collagen fibres from lamina propria form lops of fibres that attach basement membrane to connective tissue (made of collagen type 6)
-any defect in this d=structure can cause diseases

Question 24

What are epithelium rete pegs?

Answer 24

Epithelial extensions that project into underlying connective tissue

Question 25

Structure of submucosa

Answer 25

-present in almost all mucosal tissues
-Mainly made of connective tissue that contains fibres, blood vessels, nerves, minor salivary glands, fat tissue

Question 26

papillae

Answer 26

keratinised mucosa with sepecialised structures called papillae, some of which have taste buds

Question 27

What is tongue papillae

Answer 27

-Tiny bumps called papillae give the tongue its rough texture
-contain taste buds
-4 types
-filiform papillae-major anterior surface of tongue, Pyramidal shaped, completely keratinised, mainly mechanical function, for protection
-fungiform-embedded between filiform papillae, look like mushrooms, keratinised, hgihly vascularised, contain taste buds
-foliate-square shaped, resemble leaf shapes, has taste buds on side, non kertinised
-circumvallate papillae-many taste buds on sides and openings of glands of ebner

Question 28

Taste buds

Answer 28

-onion like structure, placed on papillae of togue, present in soft palates
-these cells perceive anything we eat/drink and send sensation to afferent nerve to brain

Question 29

junctions in oral mucosa

Answer 29

-Junctions between diff parts of epithelium e.g. between skin and vermilion border of lip
-Always intermediate layer in-between
-junction between vermillion border of lip and epithelium of labial lining of tongue
-border is keratinised but keratin form/type is diff between skin and vermilion border, they merge into non keratinised epithelium that covers labial lining mucosa
-mucogingival junction=junction between gingiva and mucosa that covers the bone alveolus

Question 30

cells in lamina propria

Answer 30

fibroblasts
endothelial cells
inflammatory cells

Question 31

firbosblasts

Answer 31

synthesis of fibres of extracellular matrix

Question 32

endothelial cells

Answer 32

lining of blood vessels

Question 33

inflammatory cells

Answer 33

1. macrophages-phagocytes (contain lysosomes) and antibody presenting
2. mast cells-contain histamine and heparin (allergy/inflkammartion)
3. lymphocytes- increase during inflammation

Question 34

structure of lamina propria

Answer 34

-fibres
-extracellular matrix
-blood supply, sensory nerve supply

Question 35

fibres

Answer 35

90% collagen, 8% collagen type III, 2% non-collagenous fibres

Question 36

extracellular matrix

Answer 36

hydrated gel of glycoproteins and proteoglycans