Oral histology and embryology PRACTICAL LECTURE MUDr. Marina Štruncová, Ph.D. Microscopical analyses: - Prepared slides: • labium oris (1) • palatum molle (5) • apex linguae (2) • papilla vallata (3) Quick revision: - Oral cavity - Oral mucosa and classification - Papillae ORAL CAVITY ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria Walls Walls Ceiling Floor Content WALLS • Lips ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria WALLS • Lips • Cheeks ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria WALLS ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria • Lips • Cheeks • Hard and soft palate WALLS ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria • Lips • Cheeks • Hard and soft palate • Floor of the oral cavity CONTENT • Teeth • Tongue • Gums • Uvula ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria Large salivary glands: • Sublingual • Submandibular Parotid Gland (out of the oral cavity) ORAL CAVITY (cavitas oris) vestibulum oris / cavitas oris propria CONTENT ORAL MUCOSA ORAL MUCOSA: Classification Lining mucosa (65 %) Masticatory mucosa (25 %) Specialized mucosa (10 %) Lining mucosa (65 %): - Inner side of lips and cheeks - Soft palate - Lower side of the tongue - Floor of the oral cavity - Alveolar processes ORAL MUCOSA: Classification Lining mucosa (65 %): ORAL MUCOSA: Classification - Stratified squamous epithelium: mitosis and cell differentiation - Basal membrane: layer of specialized extracellular matrix – origin of Keratinocytes - Lamina Propria: mucosal tissue > fibroblasts: production of extracellular matrix ➢ Blood vessels, nerves and glands - Tela submucosa: layer of loose connective tissue between the tunica mucosa and the tunica muscularis > connectionEdmans, JG et al., 2020 Tela submucosa Muscles Lining mucosa (65 %): ORAL MUCOSA: Classification Inner side: Salivary glands/ Mucous glands Blood vessels Nerves Red part of the lip Outer side: Sebaceous glands Sweat glands Hair follicles Blood vessels Nerves m. orbicularis oris Lining mucosa (65 %): Lip ORAL MUCOSA: Classification ORAL MUCOSA: Classification Lining mucosa (65 %): Lip Red part of the lip Inner side: Salivary glands/ Mucous glands Blood vessels Nerves Outer side: Sebaceous glands Sweat glands Hair follicles Blood vessels Nerves Two distinct parts: pars glabra (2 mm) Thinner, ventral pars villosa (asi 4 mm) Thicker, dorsal pars glabra Glabra = thin Villosa = villous Fibrous papillae ORAL MUCOSA: Classification Lining mucosa (65 %): Lip of the newborn Two distinct parts: Pars glabra • Stratified squamous epithelium with keratohylain grains in the cells • The papillae of the lamina propria vs epithelium are longer than those of the skin • In 50% of cases, contains small sebaceous glands pars glabra ORAL MUCOSA: Classification Lining mucosa (65 %): Lip of the newborn Hyperkeratotic sucking pad – pars glabra Two distinct parts: Pars villosa • Very thick stratified squamous epithelium • Numerous mucosal papillae • The papillae are highly vascularized with sensitive nerve endings • When moist, it allows better attachment to the mother’s nipple ORAL MUCOSA: Classification Lining mucosa (65 %): Lip of the newborn Hyperkeratotic sucking pad – pars villosa The structural difference between pars villosa and pars glabra gradually disappears as the child ages ORAL MUCOSA: Classification Lining mucosa (65 %): Lip of the newborn Histologicaly similar to the lips. Before and above the r. mandibulae, the Corpus adiposum buccae (Bichat's body) is inserted between the buccinator and masseter muscles. ORAL MUCOSA: Classification Lining mucosa (65 %): Cheeks - The basis is the palatine aponeurosis (composed of tendon attachments of muscles and bundles of striated fibers - mainly the tensor veli palatini muscle) - Ending in the uvula - Separated into nasal and oral parts - Lining mucosa - With purely mucinous glands (glandulae palatinae) ORAL MUCOSA: Classification Lining mucosa (65 %): Soft palate Uvula Oral side Muscle Gland Glandulae nasales ORAL MUCOSA: Classification Lining mucosa (65 %): Soft palate Non-keratinized stratified squamous epithelium Masticatory mucosa (25 %): - Gums - Hard palate ORAL MUCOSA: Classification Masticatory mucosa (25 %): - The epithelium is cornified - attrition Keratinised stratified squamous epithelium - Lamina propria of dense and unorganized collagenous tissue, firmly fused with the periosteum (mucoperiosteum) - Absent tela submucosa Edmans, JG et al., 2020 ORAL MUCOSA: Classification ORAL MUCOSA: Classification Keratinized stratified squamous epithelium Oral side Nasal side ORAL MUCOSA: Classification Masticatory mucosa (25 %): Masticatory mucosa (25 %): • Anatomical variability: Foramen incisivum Where the incisive papilla is localized (in close proximity to it) Ceiling of the oral cavity Anatomical marker for the anesthesia of the nasopalatine nerve ORAL MUCOSA: Classification Masticatory mucosa (25 %): • Anatomical variability: Raphe palati Midline area from incisive papilla to soft palate, raphe palati mucosa without glands and adipocytes Ceiling of the oral cavity ORAL MUCOSA: Classification Masticatory mucosa (25 %): • Anatomical variability: Fatty zone Borders: incisive papilla, lateral gums and premolars. Strips of dense collagen tissue, fat cells, sometimes even fat lobules. 3-5 plicae palatinae transversae rugae palatine ORAL MUCOSA: Classification Ceiling of the oral cavity Masticatory mucosa (25 %): • Anatomical variability: Gland zone The dorsal continuation of the fatty zone, with smooth mucosa, containing numerous Mucinous glands (glandulae palatinae) ORAL MUCOSA: Classification Ceiling of the oral cavity Hard palate – Gland zone (frontal section) glandulae palatinae Klasifikace orální sliznice Specializovaná (10 %): - Jazyk (papily) Tongue body - Lingua (lat.) - Glossa (gr.) Body (dorsum linguae) – specialized mucosa: - Papillae filiforme - Fungiformes - Vallatae - Foliatae ORAL MUCOSA: Classification Tongue Bottom side – lining oral mucosa Non-keratinized stratified squamous epithelium Submucosa is present Body (dorsum linguae) – specialized mucosa Partially keratinized squamous stratified epithelium Aponeurosis linguae - thickened lamina propria – to connect muscles and mucosa. Absent tela submucosa Papillae filiformes: The most numerous Along the entire dorsal surface (from apex lingualis to sulcus terminalis) Brush-like formations (height 0.5 - 1.0 mm, width 0.2 - 0.3 mm) Papillae Outgrowth of mucous tissue covered by epithelium Tongue Papillae filiformes – Scanning electron mycroscopy Papillae filiformes: Corneal epithelium – epithelial desquamation + poor oral hygiene = "coated/white tongue" Brushing the tongue is essencial and enough to get rid of it! Papillae Outgrowth of mucous tissue covered by epithelium Papillae foleateae: Occur at the back of the tongue (especially on the sides) Taste buds Papillae foleateae Papillae Outgrowth of mucous tissue covered by epithelium Papillae fungiformes: Localized on Apex linguae Mushroom-shaped projections (height 0,5–1,5 mm, width 0,5–1,0 mm) Taste buds in the epithelium Papillae fungiforme with taste budTongue Difference in queratinization Papillae Outgrowth of mucous tissue covered by epithelium Papillae vallatae: Largest papillae (height 1-4 mm, width 1-3 mm) Quantity: 7–12 just before the sulcus terminalis Immersed in the mucous membrane Deep circumpapillary groove separates the papilla from the protruding ridge Taste buds Papillae vallatae – Scanning electron mycroscopy Papillae Outgrowth of mucous tissue covered by epithelium Papily výrůstek slizničního vaziva krytý epitelem jazyka Papillae vallatae Circumpapillary groove Von Ebner Gland – serous glands Taste buds ANATOMICAL QUIZ