Histology of Oral Cavity Flashcards
The oral mucosa is composed of ___________ epithelium overlying a connective tissue layer called the ____________.
Stratified squamous; lamina propria
What is the function of the oral mucosa?
Provides protection, sensation, and secretion
What are three basic types of oral mucosa?
-
Masticatory
- Covers areas experiencing masticatory forces
- Palate
- Gingiva
-
Lining
- Buccal, labial and alveolar mucosa
- Covers floor, cheecks, lips, soft palate
-
Specialized
- Dorsal tongue surface
Which basic type of oral mucosa is being descibed below?
- Resilent and rubbery
- Not stretcy’Forms a firm base in attached gingiva and hard palate
- Does not gape after incisions
- Painful with injection or inflammation
Masticatory
Masticatory mucosa is also known as ________.
Mucoperiosteum
Which type of oral mucosa is being described below?
- Orthokeratinized
- Overlies lamina, propria, with little or no submucosa
Masticatory Mucosa
NOTE: Masticatory mucosa is also often parakeratized
What are the characteristics of parakeratinized epithelium?
- Surface cells retain pyknotic nuclei
- The granular layer has few granules of keratohyaline (filaggrin)
- Little submucos
- Prickle layer has high density of desmosomes.
NOTE: Parakeratinized is normal for oral mucosa but abnormal for skin
Which type of oral mucosa is being described below?
- Non-keratinized
- Flexible and stretchy
- Moist
- Gapes after incision
- Injection easy, but so is spread of infection
Lining mucosa
NOTE: Lining mucosa is thicker than masticatory mucosa in most areas
Which surfaces are covered by lining mucosa?
- Inside of lips
- Cheeks
- Floow of mouth
- Underside of tongue
- Soft palate
- Alveolar mucosa
Which basic type of oral mucosa is being described below?
- Nonkeratinized stratified squamous epithelium
- Has three layers, with gradual transitions
- With migration to surface, cells enlarge, but retain nuclei and do not die
- Submucosa usaully present, overlying muscle
Lining mucosa
NOTE: Lining mucosa is very thin under tongue, which is important for drug delivery
What are the layers of lining mucosa?
- Superifical layer
- Intermediate layer
- basal layer
- Lamina propria
- Submucosa
- Muscle
The ________ contrasts the keratinized masticatory mucosa of attached gingiva with nonkeratinized lining of mucosa of alveolar mucosa.
Mucogingival Junction
Label
Characteristics of attached gingiva
- Keratinized (or parakeratinized) epithelium
- Many large collagen bundles in lamina propria to attach to periosteum (stippling)
- High rete pegs (epithelial extensions projecting into the underlying connective tissue)
- No submucosa (mucoperiosteum)
- Pale pink or darkly pigmented.
Characteristics of alveolar mucosa
- Thicker nonkeratinized epithelium
- Loose lamina propria with elastic fibers
- Thick submucosa
- Bright pink; vasculature is rich and lies near the epithelium
- Minor salivary glands in submucosa
Type of lingual papillae
- Filiform
- Circumvallate
- Fungiform
- Foliate
Which type of papillae is being described below?
- No taste buds
- Very sensitive to touch
- Cones of thick keratinized epithelium, only located on anterior 2/3rd
- Nonkeratinized areas in between
- Reduced with age
Filiform papillae
NOTE: A= Thick keritinazed epithelium; B= Nonkeratinized areas
Which type of papillae is being described below?
- Few
- Larhe
-
Each surrounded by deep trench containing taste buds
- Surface is covered by keratinized epithelium, but trench walls are nonkeratinized
Circumvallate papillae
Label
Which type of papillae is being described below?
- Scattered between filiform papillae on tip of tongue
- Red because of highley vascular core and thin epithelium
- Taste buds are most present on superior surface
- Sensitive to touch, as well as taste
Fungiform Papillae
Which type of papillae is being described below?
- Leaflike folds on lateral margin of posterior tongue
- Few taste buds in lateral walls
- Nonkeratized epithelium
- Lost with age
Foliate Papillae
*Note lymphoid tissue in opposing fold
Label
Lingual Tonsil
NOTE: Lingual tonsil is a collection of lymphoid follicles, which crypts opening onto the surface of the tongue. Covered by nonkeratized epithelium
The lingual tonsiled is lined by ________ epithelium.
Non-keratinized lining epithelium
Turnover time
Time necessary to replace all cells
*Very rapid in oral mucosa
NOTE: The quick turnover rate allows rapid, scar-free healing, but tendency to oral ulcers under chemotherapy
Approximate cell turnover in oral mucosa
Label
A = enamel,
B = dentin
D = pulp,
E = alveolar bone
F = periodontal ligament
What are the 4 main components of teeth?
- Enamel
- Dentin
- Dental pulp
- Peridontal ligament
Which major component of teeth is being described below?
- Hardest biological tissue, but brittle
- 96% minaral crystals
- Little matrix
- Avascular; non-vital
- No nerves
- Non-renewable
- Ionic exchange with saliva
Enamel
Which major component of teeth is being described below?
- Harder than bone
- Resilient, slightly elastic
- 70% mineral, 20% protein matrix, 10% water
- Smaller crystals
- Blood vessels and nerves
- Grows through life
- Can repair itself
Dentin
A= dentin
B= enamel
Dental pulp is made up of __________ tissue.
Loose connective tissue
Function of dental pulp
Forms, maintains, and repairs dentin
NOTE: Dental pulp is especially rich in blood and nerve supply and continues to function and form dentin throughout life
The periodontal ligament is made of _______ tissue.
Dense fibrous connective tissue
Function of periodontal ligament
Secures teeth to jaw
Gomphosis
Peg and socket joint that contains proprioceptors for protective reflexes
Functions of saliva
- Lubrication during mastication, swallowing, and speech
- Buffering
- Ions for maturation and maintenance of tooth enamel
- Growth factrs for wound healing and maintenance of mucosa
- Antibacterial, antiviral
- Initiation of digestion
- Taste: Solubilize food, flush and maintain taste buds
3 Major Salivary Glands
Parotid
Submandibular
Sublingual
Xerostomia
“Dry mouth”
- May be caused by radiotherapy, loss of innervation, autoimmune diseases or anti-cholinergic drug effects
- Leads to rampant caries, mucosal infections, fungal infections, atrophy of oral mucosa, and difficulties in tasting, swallowing and speaking
Normal flow of saliva
500-750 ml/day
Which salivary glands are mediated by nerves?
parotid and submandibular
NOTE: Minor glands and sublingual secrete continuously
_______ (parasymphatetics/sympathetics) stimulate fluid flow. ___________(parasympathetics/sympathetics) decrease fluid.
Parasympathetics; sympathetics
____________ (parasympathetics/sympathetics) activete protein exocytosis.
Sympathetics
Label
Characteristics of serous secretion
- Round nuclei in base
- Basal basophilic rER
- Extensive Golgi
- Apical secretions granules
Mechanism of serous secretion
- Active transport of ions into cell draws water in
- Apical anion channels open with parasympathetic activation, drawing ions and water into the lumen, creating and isotonic primary saliva
- As saliva moves through ducts, salt is pumped out, leaving a hypotonic saliva
___________ cells encircle acini and intecalated ducts.
Myoepithelial cells
NOTE: Myoepithelial cells lie between the epithelial secretory cells and the basal lamina
Function of myoepithelial cells
Creates secretory pressure
Label
SA= Serous acini
InD= Intercalated ducts
____________ express isotonic fluid into intercalated ducts, then into striated ducts with simple columnar epithelium.
Serous acini
Which ions are added in the striated duct?
Bircarbonate
Kallikrein
K+
Characteristics of mucous secretion
- Nuclei flat and compressed agaist basal edge
- Apical cytoplasm filled with poorly stained mucous secretory granules
- Lumen is larger and more tubular
- Golgi and rER present, but constricted
Mucin granules are discharged under ______ control.
Nervous
Serous demilunes are an artifact of _________.
Fixation
NOTE: All secretory cells contact the lumen
Characterize each salivary gland as serous, mucous or mixed.
Parotid gland
- All serous acini; fat cells
Submandibular
- Mixed; mostly serous
Sublingual
- Mixed; mostly mucous
Characteristics of minor salivary glands
- No capsule (not so painful with swelling)
- Rich in mucins, antibacterial proteins and IgA
- Slow, continuous secretion
Function of (Von) Ebner’s Glands
- Release secretions into the trench surroungding the vallate papilla, flushing to enhance taste discrimination
Sjogren’s syndrome
Autoimmune disorder involving salivary and lacrimal glands
What type of gland are salivary glands?
Merocrine
Classification of Glands
