Oral Mucosa Flashcards
what are the different disease of the oral cavity and their composition
40% is caries
40% is periodontal disease
20% is oral diseases like cancer and herpes
what is the protection of the oral mucosa associated with
mechanical forces, infection and immunity
how is the oral mucosa responsible for sensation
it can recognise the texture of food through the periodontal ligament, but can also use the tongue to press the bolus against the hard palate
how can medicines be absorbed in the oral cavity
through the oral mucosa
that are the three types of oral mucosa
lining
masticatory
gustatory
where is the lining mucosa found
under the tongue
where is the gustatory mucosa found
covering the superior dorsum of the tongue
what is dyplasia of the oral mucosa
keratinisation of the lining mucosa which could be carcinoma
where is masticatory mucosa found
in areas of the oral mucosa subjected to friction and compression and therefore requires keratinisation. this happens in a process that requries cells to divide and migrate to the surface, creating a layer of cells filled with keratin.
what happens if there is loss of tissue due to friction and compression that occurs faster than keratinisation
the cell may reach the surface before complete keratinisation, which leads to parakeratinisation.
what does the masticatory mucosa cover
the hard palate and the attached gingiva
give a breakdown on the features and properties of the lining mucosa
- wide submucosa gives way for moving around
- more rapid turnover, because the cells are non keratinised and therefore take less time to form
- lining mucosa heals faster due to the rapid turnover, and can use stitches on the lining mucosa
-base of the tongue is also lining mucosa, and is the region with the greatest risk of serious lesions like cancer. - mouth has limited space for removal of cancerous lesions, and we cannot remove large portions of tissue without too much damage. this is why it is important to identify within the early stage
what is gustation
taste
where is gustatory mucosa found
the dorsum of the tongue
what is the gustatory mucosa characterised by
papillae
what are the layers of the epithelium of the oral mucosa
- stratum germinativum
- stratum spinosum
- stratum granulosum
- stratum corneum
what is the stratum germinativum layer
the basal layer where cells divide. there are mitotic figures found here
what is the stratum spinosum layer
the prickle cell layer. there are desmosomes responsible for the interconnection of epithelium, which is important when looking into cysts
what is the stratum granulosum
the granular layer. keratin becomes visible and gives the vision of granules
what is the stratum corneum
the cornified layer, which is more keratinised.
what may be different about the cornified layer of parakeratinised cells
some of the cells may have nuclei
where do the cells multiply
the basal and prickle cell layer
how do you know there is dysplasia by looking at the epithelial layers of the oral mucosa
there is mitotic figures in the corneum and granulosum layer
what is the mucoperiosteum formed from
the lamina propria interacting with the periosteum
describe the process of keratin formation
this is a process that takes time, and the cells need to go through the process. it is important to understand that keratin needs time to mature, and time will be replicated in the time that it takes for the tissue to heal
what allows the lining mucosa to move
the submucosa layer between the lamina propria and the periosteum
what is the mucogingival
the junction between masticatory and lining mucosa
describe non keratinocytes
clear cells lacking keratin
melanocytes which produce pigment melanin found on the stratum germinativum
there are also merel cells associated with the mechanoreceptors. and langerhaans cells fonud above the stratum germinativum
what do pilliform papillae look like
leaves
what do fungiform papillae look like
mushrooms
how much of the dorsum of the tongue is keratinised
all of it
what does the lip separate
the skin from the mucosa
what is geographical tongue
benign migratory glossitis, and presents as irregular smooth patches of the tongue lacking filliform papillae. there are red margins where the glossitis can be found. the pattern changes over time and is very localised. histologically it is very similar to psoriasis. corticoids can be used but they are not necessary if there are not many symptoms, although some can find discomfort with spicy foods
what are the diseases of the oral mucosa
recurrent oral ulcerations
oral infections
vesiculo bullous lesions
white patches
premalignant conditions
what are recurrent oral ulcerations
these are special in terms of treatment and cause. some recurrent ulcerations are viruses associated with auto inflammatory responses
what are vesiculo bullous lesions
bubbles forming on the tongue, when burst they become ulcerations.
what are white patches in the mouth associated with
hyperkeratinisation of the tissue.
what can premalignant conditions be associated with
ulcers, infections, lesions
what is the lamina propria
the underlying connective tissue layer of the epithelium of the oral mucosa
where is the submucosa found
between the lamina propria and the underlying bone or muscle
what is masticatory mucosa
this is where the epithelium is keratinised and is found in areas subjected to significant loading like the hard palate and the gingiva
what is the lining mucosa
this is where the epithelium is non keratinised; found in regions like the lip, cheek, and the floor of the mouth as these experience far less stress
which section of the tongue is partly keratinised
the anterior two thirds
what is the anterior two thirds of the dorsum of the tongue lined by
the gustatory mucosa
what is the lining of the posterior one third of the tongue like
non keratinised
what is the health of the oral mucosa dependent on
the quality and quantity of saliva produced by glands lying in the submucosa
what does the oral mucosa show
specialisations that allow it to fulfil several roles
what are the roles of the oral mucosa
- mechanical protection against compressive and shearing forces
- barrier to microorganisms, toxins and various antigens
- role in the immunological defence, both humoral and cell mediated
- minor glands within the oral mucosa provide lubrication and buffering as well as secretion of some antibodies
- richly innervated to provide input for touch, proprioception, pain and taste
what are the two layers of the oral mucosa
the outer layer (stratified squamous epithelium) and the lamina propria
what does the lamina propria of the oral mucosa consist of
a looser connective tissue containing fat deposits and glands
what can the oral mucosa be specialised into
- masticatory
- lining
- specialised
does masticatory have a thin or thick lamina propria
thick
which epithelial layers can be found in the oral mucosa
the stratum germinativum, the stratum spinosum, the stratum granulosum, and the stratum corneum
what are the two outer epithelial layers replaced by in lining mucoss
non keratinising superficial layer
does the epithelium have the stratum lucidum of clear cells in the oral mucosa
no
is turnover of the lining mucosa faster or slower than masticatory mucosa
faster
give a description of the stratum germinativum
single cell layer adjacent to lamina propria. there are cuboidal cells with a population of stem cells
the stem cells can differentiate to give tise to replacement keratinocytes in the epithelial layers above
the cells of the basal layer are the least differentiated cell in the oral epithelium, and contain a limited number of organelles associated with the synthesis and secretion of proteins
what is the stratum spinosum
the prickle cell layer. comprised of round cells forming a layer several cells thick. in the upper part of the prickle cell layer, there are intracellular membrane coating granules, which are rich in phospholipids and in keratinised epithelium they consist of a series of parallel lamellae
what does slight shrinkage from histological preparation of the prickle cell layer lead to
cells separating at all points where the desmosomes do not anchor them together, giving them a spiny appearance
what is the deepest layer in the prickle cell layer
the parabasal layer
give a brief description of stratum granulosum
many organelles are reduced or lost and contain large numbers of granules called keratohyaline granules
the membrane coating granules are first seen in the prickle cell layer move toward the superficial surface of the keratinocyte and discharge their lipid rich contents into the intercellular space
what is the stratum corneum
cells have lost all of their organelles including the granules
epitheial squames are shed in the process of desquamation necessitating the constant turnover of epithelial cells
what happens to allow for desquamation
desmosomes weaken and disappear
what epithelial layer provides the mechanical protective function to the mucosa
the stratum corneum
where are parakeratinised cells found
the gingiva. they contain small and shrunken nuclei
what happens to cells in the lining epithelium as they shift toward the surface
they enlarge and flatten
what do the cells in the lining epithelium lack
keratohyaline granules, and there are more organelles in the surface layer compared with those in the keratinised cells
are the layers of lining epithelium as clearly defined as in keratinised epithelium
no
what is the stratum superficiale
the outer superficial layer of lining epithelium
what is keratin
tightly packed tonofilaments surrounded by the matrix protein filaggrin
how much of the oral epithelium is made up of non keratinocytes
10%
what are some examples of non keratinocytes found within the oral epithelium
melanocytes
langerhaans cells
merkel cells
inflammatory cells that have migrated through the epithelium, like lymphocytes
what are melanocytes
pigment producing cells located in the basal layer. derived from the neural crest. present in the skin. long processes that extend in several directions and across several epithelial layers. produce melanin using tyrosinase. cytoplasm of melanocytes contains pigment that is packaged in small granules called melanosomes
what are melanosomes
pigment packaged into small granules
how many keratinocytes does a single melanocyte establish contact with
30 or 40
what are langerhans cells
dendritic cells situated in the layers above the basal layer. leave the bloodstream to enter the lamina propria before penetrating the basal lamina to reach the epithelium. they act as part of the immune system as antigen presenting cells to provide immediate protection against invading pathogens, and they quickly respond to bacterial structures.
where are merkel cells found
in the basal layer often closely apposed to nerve fibres. thought to act as a receptor and is derived from the neural crest. common in masticatory epithelia such as the gingiva, but less frequent in the lining mucosa such as the buccal mucosa
describe the lamina propria
connective tissue underlying the oral epithelium with two layers, the superficial papillary layer between the epithelial ridges and a deep reticular layer. provides mechanical support.
what are the two layers to the lamina propria
superficial papillary layer and the deep reticular layer
where is the superficial papillary layer found
between the epithelial ridges, where the collagen fibres are thin and loosely arranged.
describe the deep reticular layer
second layer of the lamina propria dominated by thick parallel bundles of collagen fibres
what is found within the lamina propria
nerves with a sensory function, blood cells and salivary glands. fibroblasts, stem cells and found substance
what are the roles of the blood vessels and salivary glands in the lamina propria
defence
describe the stem cells found within the lamina propria
they exhibit high proliferation rates and have the capacity to differentiate into several different lineages, such as fat, bone and cartilage cells. they also demonstrate the feature of immuno privilege, which may be important in tissue engineering
what does the ground substance of the lamina propria consist of
a hydrated gel of proteoglycans and glycoproteins. with all the general connective tissues, the usual defence cells are present, and macrophages can be seen here
what is the basement membrane
a complex arrangement that links the surface epithelium to the underlying lamina propria in the oral mucosa.
what do all the major products of the basal lamina appear to be synthesised by
epithelial cells
what are the two layers to the basal lamina
the lamina lucida and the lamina densa
where is masticatory mucosa found
areas with high compression and friction. characterised by a keratinised epithelium and a thick lamina propria. found in the gingiva and palate, and is firmly bound down directly to the muceoperiosteum, except for the region at the side of the palate, where a submucosa is present
why is the lining mucosa non keratinised with a loose lamina propria
it must be mobile and distensible
where is lining mucosa found in the mouth
lips
cheek
buccal and labial sulci
alveolar mucosa
floor of the mouth
ventral surface of the tongue
soft palate
break down the percentage composition that each mucosa type takes up in the mouth
60% lining mucosa
25% masticatory
15% specialised
break down the principle features and regional variations of the oral mucosa in the floor of the mouth
thin, non keratinised epithelium. the lamina propria has short and broad with collagen and some elastin fibres. the submucosa is loose and is loosely attached to underlying muscle. lining mucosa
what muscles does the lip contain and how does it aid the oral cavity
striated muscles are found in the core of the lip that are part of the muscles of facial expression
what kind of salivary glands are found in the submucosa
minor mucous salivary
what happens to epithelial thickness from the skin to the mucosa in the lips
gradually increases
is the epithelium of the vermillion zone keratinised
yes, but it is thin and translucent
describe the features of the connective tissue papillae of the lamina propria
long and narrow, contain capillary loops.
what is the labial mucosa covered by
a relatively thick, non keratinised epithelium.
describe the epithelium found on the labial mucosa
relatively thick and non keratinised
what does the vermillion zone separate
the keratinised skin from the lining mucosa
is there submucosa present in the cheeks
yes, and it contains many minor mucous salivary glands
what is the gingiva
the portion of the oral mucosa that surrounds and attaches to the teeth and alveolar bone
what are the two components of the gingiva
attached gingiva and free gingiva
what is attached gingiva
the gingiva directly bound to the underlying alveolar bone and tooth
what is free gingiva
the narrow rim of mucosa that is not bound down to an underlying hard tissue
what is the gingival sulcus
unattached region between the free gingiva and the tooth
what separates the attached gingiva from the alveolar mucosa
the mucogingival junction
what is the alveolar mucosa loosely attached to
the lower part of the alveolar bone
what allows for the wide degrees of movement that alveolar mucosa has
loose submucosa
what is the difference in appearance between the alveolar mucosa and the attached gingiva related to
differences in keratinisation and translucency
describe the alveolar mucosa
thin, non keratinised epithelium overlying a lamina propria that shoes poorly developed dermal papillae
what is found under the surface of the alveolar mucosa
underlyung blood vessels
what does the submucosa of the alveolar mucosa house
many minor mucous salivary glands and numerous loosely attached elastin fibres that allow for free movement
what is the mucosa found on the surface of the attached gingiva
masticatory
how are the papillae of the attached gingiva often aligned
in rows
how do the stipples on the surface of the attached gingiva arise
from the intersecting epithelial ridges
what is the lamina propria bound to
the bone - forms the mucoperiosteum
what constitutes the crevicular epithelium and the junctional epithelium
the epithelium on the inner surface of the gingiva
describe the interface of the crevicular epithelium
folded with underlying connective tissue
describe the junctional epithelium
this is the epithelial collar that surrounds the tooth and extends from the region of the cementum enamel junction to the bottom o fthe gingival crevice
what are the two zones of the junctional epithelium
a single cell layer of cuboidal cells overlying several layers of flattened cells equivalent to a stratum spinosum
what is the junctional epithelium derived from
the rapidly replaced reduced enamel epithelium
how does the length of the junctional epithelium attached to the enamel surface vary
according to the stage of eruption. when the tooth first erupts into the oral cavity, most of the enamel will be covered by junctional epithelium. by the time the tooth reaches the occlusal plane, about a quarter of the enamel surface is still covered by junctional epithelium.
how is the blood supply of the lamina propria associated with the junctional epithelium arranged
as a complex anastomosing network
what does the dento gingival junction do
seals the underlying connective tissue of the periodontium from the oral environment. the strength of the seal is dependent on the attachment of the junctional epithelium to the tooth as well as the pressure exerted by the fibres and tissue fluid of the underlying connective tissue.
what is the gingival crevicular fluid
the tissue fluid and cells that pass readily through the epithelium from the connective tissue into the gingival crevice
how can the gingival crevicular fluid collected
using capillary tubing, gingival washing, or absorbent paper strips
what is interdental gingiva
the gingiva between adjacent teeth
what does the shape and arrangement of the gingival tissues between the teeth depend on
the shape of the contact between the teeth
what does interdental gingiva occupy
the space between the teeth and conforms to its shape
how does the interdental gingiva appear from the buccal or lingual aspects
wedge shaped
why is it hard to keep the interdental gingiva plaque free
the epithelium is thin.
what can be seen infiltrating the underlying the lamina propria on the interdental gingiva
inflammatory cells
where do dentogingival fibres arise from
the root surface above the alveolar crest and radiate the insert into the lamina propria of the gingiva
where do longitudinal fibres extend in the gingiva
for long distances within the free gingiva and some possibly for the whole length of the arch
where are circular fibres found
encircle each tooth within the marginal and interdental gingiva. some attach to cementum, some to alveolar bone. some cross interdentally to join the fibre group of the adjacent tooth
where do alveologingival fibres run from
gingiva to alveolar bone
where do dentoperiosteal fibres occur
only in buccal and lingual gingiva and arise from cementum and pass over the alveolar crest to insert into the periosteum
where do transseptal fibres pass
horizontally from the root of one tooth above the alveolar crest, to be inserted into the root of the adjacent tooth.
where do semicircular fibres emanate from
cementum near the cementum enamel junction and cross the free marginal gingiva and insert into a similar position on the opposite side of the tooth
where do transgingival fibres arise from
cementum near the cementum enamel junction and cross the free marginal gingiva and insert into a similar position on the opposite side of the tooth
what do transgingival fibres do
they reinforce the circular and semicircular fibres
where do vertical fibres arise
in alveolar mucosa or attached gingiva and pass coronally toward the marginal gingiva and interdental papilla
what does the submucosa of the hard palate contain
main neurovascular bundles. the minour mucous glands that open onto the surface by ducts and adipose tissue
what is the nasal surface of the hard palate lined by
- respiratory mucosa, consisting of ciliated columnar epithelial cells with many goblet cells. beneath this epithelium there is a vascular submucosa containing minor glands of both mucous and serous types
describe the connective tissue papillae of the soft palate
short and broad
what does the broad submucosa of the soft palate contain
many small mucous glands
what are the ventral surface of the tongue and floor of the mouth covered by
typical lining mucosa. there is a little wear and tear but a need for considerable mobility
describe the epithelium of the floor of the mouth
thin, non keratinised showing short papillae. an extensive submucosa
why can drugs rapidly reach the bloodstream via the floor of the mouth
the thinness of the epithelium and vascularitu of the connective tissue
what is the sulcus terminalis
this divides the tongue into an anterior two thirds and a posterior one third. the anterior is the palatal surface, and the posterior is the pharyngeal surface
how can papillae be classified
into filiform, fungiform, foliate and circumvallate papillae. foliate may be present as one or two longitudinal clefts at the side of the posterior part of the tongue. circumvallate are large and rounded
what are the clinical considerations of the oral mucosa
- lingual thyroid
- erythema migrans
- median rhomboid glossitis
- white lesions
what is lingual thyroid
this is a benign developmental condition. the dorsum of the posterior third of the tongue mayu show a midline swelling that represents active thyroid gland tissue that has failed to migrate from its developmental situation att he site of the foreamen caecum.
what is erthyema migrans
benign condition - inflammatory condition of unknown cause that is characterised by the recurrence and disappearance of red areas on the tongue. smooth red lesions on the tongue related to atrophy of the filiform papillae surrounded by a grey white irregular boundary. also known as geographical tongue - may be symptomless, some complain of a burning sensation. red coloration of affected areas coincides histologically with the thickening of the epithelium of the epithelium and the presence of inflammatory cells in the region
what is median rhomboid glossitis
benign abnormality seen in the midline of the dorsum of the tongue at the junction between the anterior two thirds and posterior third. nodular red or pink region devoid of papillae. harmless and symptomless.
what are white lesions associated with
areas of keratinisation in normally non keratinised lining mucosa. linea alba - mildest white lesion in the buccal mucosa and is level with the occlusal plane - the result of low grade trauma upon the folds of cheek mucosa trapped between the teeth. lichen planus - common chronic inflammatory disease that produces white striated lesions in the mouth usually in the buccal mucosa
what can white patch lesions develop into
malignancies - should be kept under observation. change in form to a speckled appearance associated with a firmness on palpation, ulceration and a rolled border may signify a malignant change.
what may signify a malignant change in white patch lesions
change in the form to a speckled appearance associated with a firmness on palpation, ulceration and a rolled border
what is found on the inner surface of the lip
mucosa
what is the vermillion zone
the junction on the lip between the skin and the mucosa
break down the principle features and regional variations of the oral mucosa in the soft palate
thick non keratinised epithelium. the lamina propria has short papillae with many elastin fibres. the submucosa is loose and is loosely attached to the underlying tissue. lining mucosa
what is found on the outer surface of the lip
skin
break down the principle features and regional variations of the oral mucosa in the hard palate
thick keratinised epithelium. the lamina propria has long papillae with dense collagen in submucosa laterally, but the lamina propria firmly bound to the periosteum without the submucosa in the midline. masticatory mucosa
break down the principle features and regional variations of the oral mucosa in the anterior two thirds of the dorsum of the tongue
thick primarily keratinised epithelium. the lamina propria has long papillae with collagen and some elastin fibres. the submucosa is not a very distinctive layer and is attached to the underlying muscle. specialised gustatory mucosa.
break down the principle features and regional variations of the oral mucosa in the ventral surface of the tongue
thin non keratinised epithelium. the lamina propria has short and numerous papillae with collagen and some elastin fibres. the submucosa is not very distinctive, and is attached to the underlying muscle. lining mucosa
break down the principle features and regional variations of the oral mucosa in the posterior third of the dorsum of the tongue
variable, generally non keratinised epithelium. the lamina propria has short or absent papillae with collagen and some elastin fibres. the submucosa is not a very distinctive layer and is attached to the underlying muscle. lining gustatory mucosa
break down the principle features and regional variations of the oral mucosa in the alveolar gingiva region
thin, non keratinised epithelium. the lamina propria has short/absent papillae and has many elastin fibres. the submucosa is loose and is loosely attached to the underlying periosteum. has lining mucosa
break down the principle features and regional variations of the oral mucosa in the labial and buccal region
a thick, non keratinised epithelium. their lamina propria have short and irregular papillae, and contain collagen and some elastin fibres. they have a dense submucosa which is firmly attached the underlying muscle. has lining mucosa
break down the principle features and regional variations of the oral mucosa in the vermillion zone of te lip
a thick, keratinised epithelium. the lamina propria is long and narrow papillae and has collagen and some elastin fibres. has dense submucosa and is firmly attached to underlying muscle. specialised mucosa
break down the principle features and regional variations of the oral mucosa in the attached gingiva region
thick, keratinised and parakeratinised epithelium. the lamina propria has long and narrow papillae, with dense collagen firmly attached to the underlying periosteum. there is no distinct submucosa. has masticatory mucosa
