MICROSCOPIC ANATOMY AND DEVELOPMENT OF GIT I Petr Vaňhara, PhD Department of Histology and Embryology LF MU pvanhara@med.muni.cz • Upper and lower lip • Vestibulum oris • Soft and hard palate • Tooth and gingiva • Tongue ORAL CAVITY ORAL MUCOSA • lamina epithelialis mucosae stratified squamous epithelium • lamina propria mucosae loose collagen C.T. Types of oral mucosa • lining mucosa - mucosal and submucosal C.T. • masticatory mucosa - parakeratinized epithelium - directly on periost (mucoperiosteum) - no submucosa • specialized mucosa - dorsum linguae – papillae LIP Mucosa Labial artery Labial glands M. orbicularis oris Labial skin Hair follicles M. orbicularis oris Vermillion border Ventral Dorsal Skin side (ventral) Oral side (dorsal) LIP Epidermis • Keratinized stratified squamous epithelium Dermis • Loose collagen C.T. • Hair follicles • Sebaceous glands • Sweat glands Oral mucosa • Stratified squamous epithelium • Loose collagen C.T. • Small salivary labial mixed glands LIP Vermillion border • Eleidin protein • salivary glands hair follicles, sweat glands absent • high c.t. papillae, capillaries • nerve endings, Meissner’s corpuscles torus labialis newborns pars glabra pars villosa TONGUE TONGUE TONGUE – APEX LINGUAE Dorsum linguae Facies mylohyoidea Musculi linguae Glandula lingualis anterior TONGUE – MUSCLES • Intraglossal • Extraglossal TONGUE – MUSCLES Extraglossal Intraglossal Septum linguae Aponeurosis linguae TONGUE – GLL. LINGUALES ANTERIORES (BLANDINI) TONGUE – FACIES MYLOHYOIDEA TONGUE – DORSUM LINGUAE • specialized mucosal structures - papillae • submucosal C.T. is absent TONGUE – FILLIFORM PAPILLAE TONGUE – FILLIFORM PAPILLAE TONGUE – FUNGIFORM PAPILLAE TONGUE – FUNGIFORM PAPILLAE TONGUE – FILLIFORM AND FUNGIFORM PAPILLAE TONGUE – FOLIATE PAPILLAE TONGUE – VALLATE PAPILLAE TONGUE – VALLATE PAPILLAE TONGUE – TASTE BUDS TONGUE – TASTE BUD • Intraepithelial • porus gustatorius • 2000-8000 in oral cavity • 60-80 cells • 70-80 m  30-40 m • microvilli on sensory cells • nerve fibers TONGUE – TASTE BUD doi.org/10.1016/j.neuron.2020.03.006 • secondary sensory epithelium I. II. • n. vagus • n. facialis • n. glossopharyngeus TONGUE – TASTE BUD • bitter • sweet • umami (glutamate) • G-protein-coupled receptors • salt • acid • ion channels • CD36 • fatty acid transporter • in taste sensing olfactory epithelium is involved TONGUE – RADIX, TONSILLA LINGUALIS TONGUE – RADIX, TONSILLA LINGUALIS TONGUE – RADIX, TONSILLA LINGUALIS, WEBER’S GLANDS PALATE SOFT PALATE SOFT PALATE SOFT PALATE – EPITHELIAL CHANGE TOOTH • Anatomical  clinical crown • Neck (cementoenamel junction) • Root DECIDUAL AND PERMANENT TEETH TOOTH – ENAMEL Enamel, 1-2 mm • Covers the crown • Made by ameloblasts, but after eruption acellular • No regeneration • 96% Ca-hydroxyapatite, enamel prisms • Enamelins, amelogenins, ameloblastins • Striae of Retzius (incremental growth lines) 10.1007/978-1-4020-5845-5_11 TOOTH – ENAMEL TOOTH – CEMENTUM Cementum, 100-500 µm • Covers root and neck • Cementoblasts/cementocytes • Regenerates • 50% Ca-hydroxyapatite • Collagen I, III, XII, GAGs, proteoglycans • Sharpey’s fibers – fibrilal cementum • Periodontal ligaments – tooth alveolus TOOTH – CEMENTUM TOOTH – DENTIN Dentin • Odontoblasts • Regenerates • 70% Ca-hydroxyapatite • Collagen I, glykoproteins, proteoglycans • Odontoblast processes –Tomes’ fibers • Owen’s lines • Von Ebner’s lines (incremental) • Nerve fibers TOOTH – DENTIN TOOTH – ODONTOBLASTS odontoblasts predentin dentin subodontoblastic zone pulp TOOTH – ODONTOBLASTS pulp odontoblasts predentin dentin cementum periodontium TOOTH – DENTIN cementum periodontium dentin subodontoblastic zone odontoblasty predentin TOOTH pulp dentin cementum periodontium bone TOOTH TOOTH – PULP • soft connnective tissue similar to embryonic mesenchyme • rich vascularisation and innervation • crown pulp and rooth canal • foramen apicale - periodontium • odontoblasts • nociceptive nerve plexus (plexus Raschkowi) https://www.slideshare.net/hesham63 /pulp-15597098 Gingiva ‐ free (marginal, g. libera) ‐ attached (g. affixa) ‐ paramarginal groove (outer gingival groove) ‐ sulcus gingivalis ‐ gingivodental junction of Gotlieb ‐ stratified squamous epithelium ‐ lamina propria mucosae – dense collagen c.t. TOOTH – PERIODONTIUM AND GINGIVA TOOTH – PERIODONTIUM AND GINGIVA • small (gll. labiales, buccales, retromolares, palatinae, gll. lingualis anterior, gll. Ebneri, gll. Weberi) • large (gl. parotis, gl. submandibularis, gl. sublingualis) SALIVARY GLANDS see GIT 3 SALIVARY GLANDS – GL. PAROTIS SALIVARY GLANDS – GL. PAROTIS SALIVARY GLANDS – GL. SUBMANDIBULARIS SALIVARY GLANDS – GL. SUBLINGUALIS PHARYNX • nasopharynx • oropharynx • laryngopharynx DEVELOPMENT OF FACE DEVELOPMENT OF FACE stomodeum nasal placode stomodeum 2nd pharyngeal arch processus maxillares processus mandibularis 2nd pharyngeal arch DEVELOPMENT OF FACE DEVELOPMENT OF FACE 4th week DEVELOPMENT OF FACE • nasal pits surrrounded by paired prominences – medial and lateral nasal prominence • area triangularis (nose) • intermaxilary segment (medial part of upper lip, part of upper jaw, primary palate) DEVELOPMENT OF FACE • maxillary prominences fuse with 1. intermaxillary segment 2. lateral nasal prominences • sulcus nasolacrimalis DEVELOPMENT OF FACE http://www.youtube.com/watch?v=4LQJIf0XLP0 DEVELOPMENT OF FACE DEVELOPMENT OF FACE - PALATE • primary palate (intermaxillary segment) • secondary palate (lateral palate shelves DEVELOPMENT OF FACE - PALATE DEVELOPMENT OF TONGUE Pharyngeal arches: I. tuberculum linguale laterale (dx. wt sin.) (paired) and tuberculum impar → apex and corpus III and IV. copula and eminentia hypobranchialis → radix DEVELOPMENT OF VESTIBULUM ORIS Vestibular lamina • Dental lamina • Labiogingival lamina 1. Mandible 2. Dental lamina 3. Dental papilla 4. Enamel organ 5. Labiogingival lamina 6. Meckel's cartilage 7. Oral epithelium 8. Tongue http://www.chronolab.com/atlas/embryo/histo_head.htm 1. Eye 2. Mandibular bone 3. Maxillary bone 4. Nasal cavity 5. Nasal septum 6. Oral cavity 7. Palatine process 8. Tongue • Nasal canals – primitive choans • Nasal septum – from area triangularis – fusing with secondary palate DEVELOPMENT OF VESTIBULUM NASI DEVELOPMENT OF TOOTH Interactions of ectoderm and mesenchyme • primary dental lamina – teeth primordia • Inititation stage • tooth bud (primordium) • cap stage • bell stage (enamel organ, ectoderm), dental pulp (mesenchyme) DEVELOPMENT OF TOOTH • bell stage – enamel, differentiation of odontoblasts from cells of dental pulp • enamel prisms and dentin matrix • dental sac DEVELOPMENT OF TOOTH • enamel organ (inner and outer ambelobalsts, stratum intermedium stellate reticulum - pulp) – prisms • odontoblast differentiation - dentin matrix, (processes of odontoblasts = Tomes fibers) DEVELOPMENT OF TOOTH root development – tooth eruption cervical loop → Hertwig epithelial root sheath DEVELOPMENT OF TOOTH DEVELOPMENT OF TOOTH ABNORMALITIES OF FACE DEVELOPMENT - CLEFTS • upper lip (cheiloschisis) – lateral (uni, bi), medial • lower lip – medial, always combined (jaw, tongue) – gnathoschisis et cheiloschisis inf. • oblique cleft (fissura orbitofacialis) • transferse cleft (fissura transversa) Soft tissue clefts ABNORMALITIES OF FACE DEVELOPMENT - CLEFTS • upper jaw - between 2nd incisor and canine - unilateral or bilateral - always combined with palate cleft (cheilognathoschisis) • palate (palatoschisis) - primary (before foramen incisivum) - secondary (behind foramen incisivum) • combined: cheilognathopalatoschisis Hard tissue clefts http://www.youtube.com/watch?v=agmSH8_mLz0 ABNORMALITIES OF FACE DEVELOPMENT - CLEFTS PHARYNGEAL APPARATUS PHARYNGEAL APPARATUS PHARYNGEAL APPARATUS PHARYNGEAL APPARATUS Derivatives • Face including soft tissues • Mimic and mastication muscles • Tongue • Outer and middle ear • Hyoid bone • Laryngeal cartilages • Thymus • Parathyroid glands • Fossa tonsillaris (→ t. palatina) • Large arteries (for details see the lesson on cardiovascular systém development) PHARYNGEAL APPARATUS PHARYNGEAL APPARATUS Derivativeof ectodermalridge Pharyngealarch Aorticarch Cranialnerve Exampleof branchiomeric muscles Skeletal derivatives Derivativeof endodermal pouch 1. external acoustic meatus 1 mandibular a. maxillaris V. trigeminus mastica- tory incus, maleus lig. sphenomandib. Meckel cartilage middle ear cavity, tuba auditiva 2-4. disappear 2 hyoid a. stapedia a. hyoidea VII. facialis mimic stapes proc. styloideus, hyoid cartilage. fossa tonsillaris 3 a. carotis interna IX. glosso- pharyngeus m. stylopha- ryngeus hyoid cartilage thymus, parathyroid bodies (inf.) 4 a. subclavia dx. a. arcus aortae X. vagus svaly faryngu a laryngu laryngeal cartilages parathyroid bodies (sup.) THANK YOU FOR ATTENTION pvanhara@med.muni.cz http://www.histology.med.muni.cz