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DIGESTIVE SYSTEM

Explore the components of the oral cavity, lips, cheeks, palate, gums, tongue, and more in detail. Learn about tooth anatomy, histology, taste buds, and salivary glands. Discover the development of teeth and the process of odontogenesis.

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DIGESTIVE SYSTEM

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  1. DIGESTIVE SYSTEM Part 1: Oral cavity and associated structures

  2. DIGESTIVE SYSTEM includes Digestive tube • Oral cavity • Esophagus • Stomach • Small intestine • Large intestine and Large extrinsic glands • Major salivary glands • Pancreas • Liver

  3. Oral cavity mucosa • Masticatory • Lining • Sensory Constituents: • Stratified squamous epithelium (nonkeratinized, or parakeratinized, or keratinized) • Subepithelial connective tissue (lamina propria mucosa + tela submucosa) • Oral cavity is characteristic by lack of lamina muscularis mucosae

  4. Oral cavity constituents • Lips • Cheeks • Palate • Gingiva (Gums) • Teeth • Tongue • Salivary glands • Tonsils

  5. Lip • Cutaneous (exnernal) aspect • Stratified squamous keratinized epithelium • Hair follicles with hair shafts • Sebaceous glands • Transitional part (vermilion zone) • Stratified squamous para-keratinized epithelium • High connective tissue papillae with blood vessels • Mucous (internal) aspect • Stratified squamous non-keratinized epithelium • Small labial salivary glands • M.orbicularis oris skeletal muscle is having central location

  6. Вчена рада Львівського національного медичного університету клопоче про надання бюджетного фінансування на 2012р. на продовження виконання перехідних тем: • Вплив гострого інфаркту міокарда, артеріальної гіпертензії та цукрового діабету 2 типу на ультраструктурне ремоделювання міокарда і розвиток серцевої недостатності (фундаментальні дослідження) Виконання теми заплановано на 2011-2013 рр. • Вивчити особливості формування травматичної хвороби головного мозку (прикладні дослідження) Виконання теми заплановано на 2010-2012 рр.

  7. Cheek • Lining mucosa • Stratified squamous non-keratinized epithelium with prominent connective tissue investment • Buccal salivary glands • Stratum musculare (skeletal muscle) • Zona adiposa • External cutaneous layer • Topographically cheek includes three parts • Pars maxillaris • Pars mandibularis • Pars intermedia

  8. Gingiva (gums) • Gingiva is covered by fully or partially keratinized (parakeratinized) epithelium with high connective tissue papillae • As the epithelium of the gingiva approaches the tooth it attaches to the enamel surface, forming a collar around the neck of the tooth, and is known as junctional epithelium • The 1-2-mm deep space between the gingiva and the tooth is the gingival sulcus

  9. Palate The oral and nasal cavities are separated from each other by hard palate and soft palate • The hard palate contains bony shelf, is immovable, is covered by masticatory mucosa on the oral and respiratory epithelium on the nasal aspect; it is rich in adipose tissue and mucus-secreting salivary glands • The soft palate is movable, its core is formed by skeletal muscle and dense irregular connective tissue; orally is covered by lining mucosa • The most posterior extension of the soft palate is the uvula, solely covered by stratified squamous non-keratinized (lining) epithelium

  10. Tongue Bulk of the tongue is composed of skeletal muscle fibers (extrinsic and intrinsic). Sulcus terminalis subdivides tongue into root and anterior 2/3 Dorsal surface of the tongue includes • Filiform papillae (conical in the newborns) • Fungiform papillae (contain taste buds) • Circumvallate papillae (contain taste buds) • Lenticulate papillae (lingual tonsil) Lateral surface of tongue includes • Foliate papillae Undersurface is covered by lining mucosa

  11. Taste buds include • Basal cells (type IV cells) • Dark cells (type I cells) • Light cells (type II cells) • Intermediate cells (type III cells)

  12. Taste buds location and structure

  13. Tooth anatomy • Crown • Neck • Root • Pulp cavity • Apical foramen

  14. Tooth histology • Enamel ↔ Enamel prisms (Enamel rods) • Dentin ↔ Collagen fibers + Dentinal tubules + Processes of odontoblasts • Cementum ↔ Collagen fibers + Cementoblasts + Cementocytes • Dental pulp ↔ Cell bodies of odontoblasts + Pulpocytes • Periodontium ↔ Collagen fibers

  15. Light micrograph of the crown and neck of a tooth

  16. Tooth development (Odontogenesis) • Dental lamina • Tooth germ: (1) Bud stage; (2) Cap stage; (3) Bell stage: - Enamel organ ↔ Ameloblasts (Enameloblasts) + Enamel cuticle - Dental papilla ↔ Odontoblasts (Dentinoblasts) + Dental pulp • Dental sac ↔ Cementoblasts (Cementocytes) + Periodontal ligament • Root formation (Hertwig epithelial root sheath)

  17. Odontogenesis

  18. Ameloblast and odontoblast schematic representation

  19. Salivary glands Major salivary glands • Parotid • Submandibular • Sublingual Minor salivary glands • Labial • Buccal • Lingual • Palatine • Molar

  20. LARGE SALIVARY GLAND STRUCTURE Cellular composition of secretory units (acini): • Serocytes (parotid) • Serocytes (serous demilunes) + mucocytes (submandibular) – • Mucocytes + serocytes (sublingual) • Myoepitheliocytes (all three glands)

  21. LARGE SALIVARY GLAND STRUCTURE Duct system: • Intercalated ducts • Striated ducts • Interlobular ducts • Common salivary duct

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