Structure and Function of Oral Mucosa Handout 2021.pdf

BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Recommended Text (essential reading): Ten Cate's Oral Histology: Development, Structure, and Function, 9th Edition by A. Nanci, 2017, Elsevier ISBN 9780323485241: Chapter 12 Oral Mucosa or Oral Anatomy, Histology and Embryology, 5th Editi...

BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Recommended Text (essential reading): Ten Cate's Oral Histology: Development, Structure, and Function, 9th Edition by A. Nanci, 2017, Elsevier ISBN 9780323485241: Chapter 12 Oral Mucosa or Oral Anatomy, Histology and Embryology, 5th Edition by B.K.B. Berkovitz, G.R. Holland and B.J. Moxham, 2018, Elsevier ISBN-10: 9780723438120: Chapter 14 Oral Mucosa Vertical integration. The following lectures are assumed prior knowledge and overlapping areas from BDS 1: Cell Structure, Cytoskeleton, cell adhesion and motility, Histology of the GI tract, Taste and Smell and Periodontal and Peri-implant tissues in health: anatomy and function Function of the oral mucosa: Protection Sensation Secretion Mucosa = epithelium + lamina propria (corium) What is the boundary between the mucosa and submucosa in the oral and intestinal epithelia? Epithelium Lamina propria Submucosa Identify the connective tissue papillae. Note the differences in the architecture and thickness of the epithelium. Which of these slides are from the palate, buccal mucosa and floor of mouth? BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Match the following terms in the figure legend: Lining Masticatory Specialised Mucoperiosteum - In the gingiva and parts of the hard palate, the oral mucosa lies in continuity with periosteum without any intervening submucosa. What is the functional and clinical significance of the mucoperiosteum? Stratified squamous epithelium - The epithelium of the oral mucosa maintains structural integrity by a process of continual renewal. The cells of the oral epithelium may be considered as comprising two functional populations: Progenitor population Maturing population Maturation Progenitor compartment contains: Stem cells Amplifying cells Turnover time: Gingiva 41-57 days Buccal mucosa 25 days Proliferation BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj The basal layer (stratum basale) is the layer of cuboidal or columnar cell immediately adjacent to the basal lamina. Mitosis in basal layer Basal lamina Diagrammatic representation of the junction between basal layer and lamina propria Diagrammatic representation of the principal components of the basal lamina Clinical significance of the basal lamina Separation of the epithelium from the lamina propria Pemphigoid – a blistering disease characterised by autoantibodies to the bullous pemphigoid antigen BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Prickle cell layer Prickle cell layer (stratum spinosum). Identify the intercellular bridges (‘prickles’) Schematic representation of desmosomes Clinical significance of desmosomes Intra-epithelial separation Pemphigus – characterised by autoantibodies to desmoglein How does the separation differ from that of pemphigoid? Granular layer Cornified layer Keratinising stratified squamous epithelium Keratohyalin granules release filagrin precursors which aggregates keratin resulting in flattening of keratinocytes Synthesis and cross-linking of other proteins e.g. loricrin, involucrin and small proline-rich proteins form the cornified envelope which eventually replace the plasma membrane of cells in the cornified layer. BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Non-keratinising stratified squamous epithelium Which areas of the oral cavity are covered by nonkeratinising stratified squamous epithelium? What are the differences between keratinising and non-keratinising stratified squamous epithelium? Lower lip Vermillion zone: Border between oral mucosa and skin Lacks skin adnexae and salivary glands Capillary loops lie in close proximity to surface Vermillion zone Skin Labial mucosa BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Specialised mucosa Where on the tongue are the following located? Fungiform papillae Filiform papillae Foliate papillae Valate papillae Filiform papillae Cross refer to Dr G. Carpenter’s lecture on Taste & Smell Taste bud Circumvalate papillae S100 immunohistochemistry BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Palatine tonsil Lingual tonsil Palatine tonsil Identify the crypt Immunohistochemistry highlighting the reticulated crypt epithelium BDS 2 Structure and Function of the Oral Mucosa Dr S Thavaraj Non-keratinocytes within the oral epithelium Langerhan Cells Antigen presenting cells Supra-basal Birbeck granules Derived from bone marrow Move in/out of the epithelium Dendritic CD1a and S100 +ve Melanocytes Neural crest derivatives Dendritic, no desmosomes Synthesize melanin in melanosomes Ubiquitous S100, HMB45 and MelanA +ve HMB45 immunohistochemistry highlighting melanocytes Complete the table below by stating the function of non-keratinocyte cells within the oral epithelium Cell Function Langerhan cells Melanocytes Merkel cells Lymphocytes Further questions to direct your revision: What other non-keratinocytes are present within oral epithelium? What are the differences between skin and oral mucosa? What are the key features of crevicular (sulcular) and junctional epithelium? What cells make up the lamina propria? What are keratins, what is their function and how may they be classified? All answers can be found in the recommended text.