Week 10 - Histology of Oral Mucosa Flashcards
What is histology
the study of the microscopic anatomy of cell and tissues of plants and animals
What are different tissues of the oral cavity
- Oral mucosa
- Teeth (enamel, dentine and pulp)
- Periodontal tissues (alveolar bone, periodontal ligament, cementum and gingiva)
- Salivary glands (major and minor salivary glands)
- Bone
- muscles
- nerves
What are the 3 main parts of the oral mucosa
- Oral epithelium
- Lamina propria (connective tissue)
- Submucosa
What type of cell comprises oral epithelium
stratified squamous
What are the 2 types of oral epithelium
- Keratinized
- Non-keratinized
What are the cell layers in keratinized oral epithelium
- stratum corneum (cornified cell layer)
- stratum granulosum (granular cell layer)
- stratum spinosum (prickle cell layer)
- stratum Basal
What are the main characteristics of the stratum corneum (cornified cell layer)
- nuclei and organelles disintegrated
- cells filled with keratin
- desmosomes disappear to allow cells to be shed away
What are the main characteristics of stratum granulosum
3-5 cell layers above the stratum spinosum
* Contain large number of keratohyalin granules
What are keratohyalin granules
Keratohyaline granules help to form the matrix of keratin fibres of the stratum corneum layer - they help bind the keratin fibers of the stratum corneum layer
What are the characteristics of stratum spinosum
- several cell layers thick
-Contains several tonofilaments (fine proteins), they also bundle to form a tonofibril - Desmosomes increase in number and become more obvious - therefore gives a prickly appearance
What are the main characteristics of stratum basale
- Single layer of cuboidal cells
- Adjacent to lamina propria
- Almost constant mitosis producing daughter cells where 1 become the superior cell layers, while the other remains as a stem cell
- Cells are connected by desmosomes, hemidesmosomes, intermediate, tight and gap junctions-
What are the cell junctions found in the stratum basale (5)
- desmosomes
- hemidesmosomes
- Intermediate junctions (adherents junctions)
- gap junctions
- tight junctions
What are desmosomes
- provides cell to cell adhesion (adjacent cells)
- Provides adhesion through intermediate filaments (type of protein)
What are hemidesmosomes
- Stud like structures found in keratinocytes that attach to the extracellular matrix
- Attaches cells to the basal lamina (where as desmosomes attach to adjacent cells)
- Uses intermediate filaments to create adhesion
What are intermediate junctions (adherents junctions)
- These are cell to cell adhesions and cell to extra cellular adhesions
- Uses actin filaments to provide adhesion (actin filaments are the same as intermediate filaments but they a smaller)
What are gap junctions
- They are communicating junctions which allow the direct chemical communication between adjacent cell cytoplasm through diffusion
- This occurs through a special type of protein
What are tight junctions
Main function is to prevent leakage of solutes and water and seals between the epithelial cells
What are the 2 types of keratinized oral epithelium
- ortho-keratinized
- para-keratinized
What is ortho-keratized oral epithelium
keratinized oral epithelium which has no nuclei or organelles
What is para-keratinized oral epithelium
Keratinized oral epithelium where the cells may retain nuclei but they are small and shrunken.
Where is para-keratinized oral epithelium found
gingiva
What is non-keratinized oral epithelium
- Cells are non-keratinized at the surface
- No keratohyalin granules
- More organelles in the surface layer
What are the cell layers of non-keratinized oral epithelium
- Superficial cell layer (stratum superficial)
- Intermediate Layer (stratum intermedium)
- Basal cell layer
What are some non keratinocyte cells
Melanocyte
langerhan cells
merkel cells
