Oral Mucosa Flashcards
What is the mouth, nasal passages, and GI tract lined by?
Mucous membrane
What 2 tissues make up a mucous membrane?
Epithelium
Underlying Connective tissue
What makes up the underlying connective tissue?
Lamina propria
Sometimes the submucosa
What layer are blood vessels located in the mouth?
Lamina propria or Submucosa
What layer are minor salivary glands located?
Submucosa
Where are ducts from minor and major salivary glands located?
Travel through the connective tissue to communicate with the mucosal surface
What are the functions of oral mucosa?
Protection
Aid in digestion
Sensory innervation
What are the types of protection the Oral mucosa provieds?
Barrier
Anti-microbial
Barrier defense of oral mucosa
Epithelium provides a physical barrier for things to not come into contact with deeper underlying tissues
Anti-microbial defense of the oral mucosa
Immune cells are found mostly in the lamina propria, but also found in the epithelium
B-defensins
Anti-microb secreted by teh superficial epithelium of the oral cavity
Large amount is secreted when there is an infection
Cysteine-rich, cationic molecule that binds to negative charges on bacterial membranes
How does the oral mucosa aid in ingestion?
Provides flexibility and a moist surface, making chewing and swallowing easier
Which is capable of more type sensation, oral mucosa, PDL, or pulp?
Oral mucosa
What types of fibers innervate pulp/dentin and what type of sensation do they provide?
C, A-delta, A-beta = mostly pain
What types of fibers innervate the PDL, and what type of sensation do they provide?
C and A-delta = pain
A-beta = proprioceptive
What types of fibers innervate the oral mucosa and what type of sensation do they provide?
A-beta = touch
A-delta and C = pain
A-delta and C = thermal
A-delta = taste
What type of cells are found in oral mucosa epithelium
Stratified Squamous epithelium
What occurs in the deep layers of the oral mucosa epithelium?
Location of cell division
What occurs at the superficial layers of oral epithelium?
This is where cells migrate, mature, become part of the surface, and then slough off
What is the turnover time for gingiva epithelium?
41-57 days
What is the turnover time for cheek epithelium?
25 days
What is the turnover time for taste buds?
10 days
What is the turnover time for junctional epithelium?
5-10 days
What is the cost/benefit of having fast turnover in epithelium
They can heal faster, but it also makes the tissues more vulnerable to conditions that affect cell division (chemotherapy, radiation, ulceration)
What are the most numerous cells of the oral mucosa?
Keratinocytes (aka epithelial cells)
What are the non-keratinocytes found in the oral mucosa?
Merkel cells
Melanocytes
Langerhans (dendritic cells)
Merkel cells
Sensory cells in the basal layer of the epithelium
Melanocytes
Pigment cells in the basal layer of the epithelium
Langerhans (dendritic) cells
Immune cells in the supra-basal layers
T/F - Different oral regions are lined by keratinized v non-keratinized epithelium
True
Describe keratinized epithelium
No organelles
Dehydrated
Tougher
Describe non-keratinized epithelium
Has organelles
Felixble
What do all epithelial cells/keratinocytes contain?
Cytokeratin
Cytokeratins
Large multigene family of proteins
Assemble into intermediate filaments to provide cytoskeletal support - mechanically tough
What are the two major groups of cytokeratines?
Type I (acidic) Type II (basic)
Cytokeratin structure
Central helical core surrounded by non-helical ends
Each cell expresses at least 2 cytokeratins (one of each type)
They assemble into coiled heterodimers
What are the strongest cytokeratin structures?
Intermediate filaments
What are the intracellular components cytokeratins?
Desmosomes and Hemidesmosomes
What do keratin mutations create
Mutations to cytokeratins, which can lead to blistering in response to minor trauma
T/F - Different epithelial layers and tissues contain the same cytokeratins
False - Cytokeratins are characterisitic of the different layers and tissues
What can changes cytokeratin expression?
Cytokeratin expression can change with disease state
Mutations in cytokeratin genes can produce regionally specific diseases
Which is more permiable, keratinized or non-keratinized epithelium?
Non-keratinized
T/F - The amount of cytokeratin only increases in the supericial layers keratinized epithelium
False - The amount of cytokeratin increases towards the superficial layers of both types of epithelium
What are the biochemical properties of Keratinized cytokeratins
They promote aggregations
They promote binding to another molecule (fillagrin)
Describe the superficial layers of Keratinized epithelium
Very flat cells
Dehydrated
No organelles
Packed with cytokeratin and fillagrin complexes
What are the biochemical properties of non-keratinized cytokeratins?
Do not promote aggregation
Can’t complex with fillagrin
Describe the superficial layers of non-keratinized epithelium
Cells are not flat or dehydrated
Retain nuclei
Cytokeratin tonofilaments
T/F - The permiability differences between keratinized and non-keratinized are due to cytokeratins
False - desmosomes contribute and are somewhat more numerous in keratinized epithelium
Membrane coating granules
Membrane bound organelles in the cell, filled with glycoproteins
1st appear in upper prickle layer
Released in more superficial layers to coat the cell
Found in both keratinized and non-keratinized cells to serve as an intercellular barrier to aqueous substances (more effective in keratinized)
Describe Membrane thickening
Envelope of 15nm cross-linked protein sheath comprised of loricrin and other proteins
Impermiable
On the inner face of keratinocytes in the upper layers of both types of epithelium
What takes up the most volume of the lamina propria?
ECM
What cells are present in the lamina propria
Fibroblasts
Macrophages
Mast cells
Other inflammatory cells
What makes up the ECM of the lamina propria
PGs, and PAGs
Glycoproteins (fibronectin)
Collagen (types I and III)
Elastin
Describe the epithelial/connective tissue interface
Scalloped
-has epithelial rete pegs, connective tissue papillae, and paipillary and reticular layers
Lining mucosa epithelium type
Non-keratinized
Describe the thickness of the epithelium in the buccal mucosa v the floor of the mouth
Buccal = thick (.5mm)
Floor of mouth = thin (.1mm)
Clinical implications of lining mucosa
Incisions more likely to gape and need to be sutured
Injections are less painful
Masticatory mucosa epithelium type
Keratinized
T/F - Lining epithelium has submucosa
True - it usually does
T/F - Masticatory mucosa has submucosa
False - it varies, but usually only in the hard palate
Clinical implications of the masticatory mucosa
Incisions don’t gape and may not require suturing
Injections are more painful
What are the three areas of the lip region?
Exterior skin
Vermillion zone
Labial mucosa
Exterior skin of lip
Keratinized
Thinnest
Sweat glands
Hair follicles
Vermillion zone
Keratinized
Thin
Blood vessels close to surface
No sweat or mucous glands
Labial mucosa
Non-keratinized
Thicker
Mucous glands
Sulcular epithelium
Part of free gingiva, which faces the tooth
Gernerally not keratinized
Junctional epithelium
Forms a ceal around the tooth
Oriented along the long axis of the tooth
Highly permiable
What are the 2 basal lamina of the junctional epithelium
External (JE/lamina propria)
Internal (JE/tooth)
What supplies vasculature for the maxilla?
Superior alveolar and palatine arteries
What supplies vasculature for the mandible?
Inferior alveolar a
Buccal a
Mental a
Sublingual aa
What are the 3 routes blood can reach its destination in a tooth?
PDL
Interdentinal septa
Oral mucosa
