Oral mucous membranes Flashcards
what are mucous membranes
- lining of a body cavity that opens to the outside
- lines the oral and nasal cavities, sinuses, trachea, stomach/intestines, urinary bladder, uterus
what are the 2 layer of mucous membranes
- epithelial layer: surface layer, kept moist by external secretions, such as mucous or serous glands (mucous/saliva)
- connective tissue: underlying layer, contains blood vessels, nerves and may have glands
what is the epithelium in the nasal cavity
- single layer, pseudo stratified columnar
- also goblet cells -> mucous (moist, trap)
- cilia at exposed end of columnar cells
what is the epithelium in the oral cavity
- called oral mucosa
- sturdier
- high friction area
- tougher, withstand constant scraping and trauma due to mastication/teeth and food
what is the tissue histologically like in the oral mucous membranes
- heavier and resistant to injury
- withstands wear and tear
- resists bacterial infection
- stratified squamous epithelium: basal layer on basement membrane (cuboidal) is layer next to connective tissue. basal layer undergoes consistent cell division (mitosis), new cells eventually reach surface
what happens to cells at the surface of oral mucous membranes
- in more protected areas (like under the tongue, inside of cheeks and lips), the cells at the surface die and slough off into saliva
- they are replaced by new cells from the basal layer
- scrape cheek -> spread on slide -> will see squamous epithelial cells
what happens to cells in more wear/tear areas of the oral mucous membranes
- found on hard palate and gingiva
- not sloughed off
- instead, cells degenerate (die) and lose nucleus
- forms non cellular keratinized layer: protective tough layer over stratified squamous epithelium -> keratinized epithelium
- wears with use
- is slowly replaced by young cells beneath
what is connective tissue
- BV and nerves composed of fibrous connective tissue
- small basement membrane separate epithelium from connective tissue
- irregular – finger like projections
- increase contact surface from which epithelium receives nutrients from the connective tissue
- thickness of CT varies in different areas of the oral mucosa
what 2 ways can connective tissue be attached in the oral cavity
- gingiva: connected to underlying alveolar bone (periosteum of alveolar process)
- cheek: connected to looser type of connective tissue -> called submucosa (larger BV, nerves, glands, fat and tissue)
what are the 3 types of oral mucosa and where are they found
- masticatory: gingiva, hard palate. most used in mastication
- lining mucosa: lips and cheeks, floor of mouth, underside of tongue. soft palate. alveolar mucosa
- specialized mucosa: dorm of tongue
what type of epithelium is gingiva
- epithelium is keratinized
- firmly attached to underlying bone
what type of mucosa is keratinized
- well keratinized and stratified
what is palatine raphe
- keratinized epithelium found on the hard palate
- directly attached to bone
what are the sides of palatine raphe like
- attached to submucosa then bone
- anterior: submucosa contains fat tissue
- posterior: submucosa contains salivary glands. ducts empty onto surface
- often inflamed in smokers (ex nicotinic stomatitis)
what is the main function of lining mucosa, what is its structure like and where is it found
- main function is to line area
- not firmly attached
- nonkeratinized
- shiny, thin
- see underlying blood vessels
- inside cheeks and lips, ventral tongue, floor of mouth, alveolar mucosa, soft palate
- underside of tongue
- ex:
- lingual frenum (folded mucosa at centre)
- sublingual fold (horizontal), right and left side of lingual frenum
- wharton’s ducts are the opening of the sublingual fold
- caruncle is opening of lingual frenum
what is alveolar mucosa
- lining mucosa
- lines oral vestibules
- nonkeratinized, shiny, red, transparent
- separated by mucogingival junction
what is the soft palate
- lining mucosa
- distal of the 8s
- underlying muscle
- salivary glands beneath mucosa empty onto its surface
what is buccal mucosa
- lining mucosa
what are fodyces granules and what might be the cause of them
- yellowish spots
- ectopic sebaceous glands (usually on skin)
- may be related to anomalies during development. during filling between max and man processes (narrowing of opening of mouth), sebaceous glands from skin become entrapped
what is specialized mucosa
- found on the dorm of the tongue
- many papillae, varies from size and shape
- some used for taste (taste buds along side surface)
- 4 different types
what are the 4 types of papillae
- filiform
- fungiform
- foliate
- circumvallate
what are filiform papillae, where are they located and what are they used for
- velvety appearance (tongue)
- thin
- covers most of tongue
- keratinized tips (kitten tongue)
- mechanical function only (no taste buds)
- smallest
- most numerous papillae
- providing the tongue with a rough surface
- aids in the manipulation and processing of foods
- aids in cleaning of the surfaces of the mouth, in particular the teeth
what are fungiform papillae, where are they located and what are they used for
- scattered among filiform
- mushroom shaped, less keratinization than filiform
- redder and larger in appearance
- contains taste buds
what are foliate papillae, where are they located and what are they used for
- lateral border of posterior 1/3 of tongue
- not well developed
- leaf shaped
- 4-11 vertical ridges
- contains taste buds
what are circumvallate papillae, where are they located and what are they used for
- back of tongue
- largest papillae
- between body and base of tongue
- inverted v shaped – 8-10
- surrounded by depression in which open ducts lead to von ebner’s glands (salivary glands), saliva trend around papilla
- aids in dissolving food -> rinsing glands (creates solution)
- saliva + food = solution that will give sensation of taste
- taste buds are particularly numerous on the lateral surfaces of these papillae
what is hairy tongue
- papillae grows constantly – shedding layer cells usually wear off (normal shedding)
- in some people, they don’t wear off
- filiform papillae grows long, traps food debris and plaque and causes a dark area on the tongue
- poor oral hygiene, antibiotics and smoking can cause hairy tongue and stain
- brush tongue to wear off papillae (filiform)
what are taste buds
- small organs (croups of specialized epithelial cells) along the lateral surfaces of papillae
- barrel-shaped
- within epithelial layer
- 30-80 cells per taste bud
- taste pore:
- food substances to enter pore (taste bud)
- detected by taste receptors
- giving sensation of taste
