Histology of the Oral Cavity PDF

Histology of the Oral Cavity YBOD200 Ms M Mahasha  Objectives  Identify and describe the microanatomy of the epithelium covering the oral cavity and lip  Describe the Microanatomy of the tongue  Describe the Microanatomy of salivary gla...

Histology of the Oral Cavity YBOD200 Ms M Mahasha  Objectives  Identify and describe the microanatomy of the epithelium covering the oral cavity and lip  Describe the Microanatomy of the tongue  Describe the Microanatomy of salivary glands  Describe and compare serous and mucous secretory units ILLUSTRATIONS & RESOURCES These are items you can copy and paste to make your slides more engaging and interesting  Oral cavity  The oral cavity is the starting point of digestion  Functions of the oral cavity:  Speech  Breathing  Facial expression ILLUSTRATIONS & RESOURCES  Sensory perception These are items you can copy and paste to make your slides more engaging and interesting  Mechanical and Chemical digestion  Mastication-the process by which ingested food is made suitable for swallowing.  The oral cavity is mainly comprised of the lips, teeth, tongue, and oral mucosa  Oral cavity  Saliva- is mainly comprised of water and a small proportion of electrolytes and proteins.  Watery component of saliva moistens and lubricates the masticatory process, while salivary mucus helps bind the bolus ready for swallowing.  Oral cavity is lined by a protective mucousILLUSTRATIONS membrane –oral mucosa, that & RESOURCES These are items you can copy and paste to make your slides more engaging and interesting contains sensory receptors for taste.  Oral mucosa has stratified squamous epithelium which is keratinized in some regions, such as the palate, due to increased friction.  Throughout the oral mucosa is numerous small accessory salivary glands – serous and mucosa  The lip  The lip is mainly made of bundles of skeletal muscle.  Has three surfaces:  External surface- hair-bearing skin  Vermillion border- pinkish-red transitional zone of the lip, and derives its colour from the rich vascularILLUSTRATIONS dermis which &only RESOURCES has a These are items you can copy and paste to make your slides more engaging and interesting thin lightly keratinized epidermal covering here.  Oral mucosa- covering the inner surface of the lip has thick stratified squamous epithelium, and the underlying submucosa has numerous accessory salivary glands. G-Accessory salivary gland M –Skeletal muscle O –Oral mucosa S –Skin V –Vermillion border The Tongue-Anterior Two-Thirds  Tongue is a muscular organ covered by oral mucosa, and has necessary receptors for taste and general sensation.  Micrograph shows circumvallate papillae and numerous filiform papillae.  Body of the tongue consists of a mass of interlacing bundles of skeletal ILLUSTRATIONS & RESOURCES muscle fibers. These are items you can copy and paste to make your slides more engaging and interesting  Mucous membrane covering the tongue is firmly bound to the CV –Circumvallate underlying muscle via dense collagenous lamina propria which is papillae continuous with the epimysium of the tongue muscle. LP –Lamina propria M –Skeletal muscle  Several small accessory salivary lands are scattered throughout the MG –Mucous glands SG –Serous glands muscle and lamina propria. Serous glands stain darker than mucous Sl–Longitudinal section glands. St –Transverse section  The Tongue: Papillae  Filiform papillae consist of a dense supporting tissue core and a heavily keratinized surface projection.  Fungiform papillae have a thin non-keratinized epithelium and a richly vascularized supporting tissue core which gives a red appearance macroscopically. ILLUSTRATIONS & RESOURCES  Circumvallate papillae are set These intoarethe tongue surface and items you can copy and paste to make your slides more engaging and interesting encircled by a deep cleft.  Aggregations of serous glands –von Ebner glands open into the base of circumvallate clefts and secrete a watery fluid that dissolves food constituents thereby facilitating taste B –Taste buds FG –Fungiform papillae reception. C –Clefts FL –Filiform papillae CV –Circumvallate VE –von Ebner glands  Papillary wall of clefts contains numerous taste buds papillae  The Tongue-Posterior One Third  Relatively smooth stratified squamous epithelium.  This overlies lymphoid tissue which contains lymphoid follicles.  All of the lymphoid tissue contributes to what is known as the lingual tonsil  The lingual tonsil, together with the palatine tonsils and the ILLUSTRATIONS & RESOURCES adenoids form Waldeyer’s ring These of lymphoid tissue are items you can copy and paste to make your slides more engaging and interesting  This ring of tissue guards the entrance to the gastrointestinal and respiratory tracts Cr –Epithelial crypts  Epithelial crypts penetrate the lingual tonsil and is also found on E–Stratified squamous epithelium palatine tonsils F –Lymphoid follicles L–Lymphoid tissue Salivary Glands  Secretory unit of the Salivary gland  Consists of tubulo-acinar structure composed entirely of serous or mucous secretory cells, or a mixture of both.  In mixed type where the mucous cells predominate the serous cells form semilunar caps called serous demilunes.  Terminal secretory units merge to form intercalated ducts & ILLUSTRATIONS which are RESOURCES These are items you can copy and paste to make your slides more engaging and interesting also lined by secretory cells, these drain into larger striated ducts.  Serous cells secrete a fluid that is isotonic with plasma, associated with reabsorption and secretion of ions.  Mucous acinus and myoepithelial cells  Mucinogen granules are poorly stained in H&E preparations.  Nuclei of mucous cells are condensed and characteristically located at the base of the cell  Both serous and mucous acini are embraced by contractile cells –myoepithelial cells which force secretion from the ILLUSTRATIONS & RESOURCES acinar lumen into the duct systemThese are items you can copy and paste to make your slides more engaging and interesting  Myoepithelial cells are flat cells with long processes that extend around the secretory acinus  These cells are located between the basal plasma M – Mucous cells membranes of secretory cells and the basement membrane My – Myoepithelial cells  Parotid Gland  General architecture of major salivary glands follows the pattern shown in the micrograph.  Gland is divided into lobules, each containing secretory units  Connective tissue septa radiate between lobules from an & RESOURCES ILLUSTRATIONS outer capsule and convey bloodThese vessels, nerves, are items you and can copy and pastelarge to make your slides more engaging and interesting excretory ducts  Parotid gland mainly consists of serous secretory units that E – Excretory ducts are darkly stained. L – Lobules  Serous cells have numerous zymogen granules which are S – Septa SC – Serous cytoplasmic granules containing proteins cells  Sublingual Gland  Mucous acini predominate sublingual glands, making them stain poorly with H&E in contrast to the serous acini in the parotid gland  A large excretory duct lined by stratified cuboidal epithelium is present in the fibrous tissue septum and is accompanied by blood vessels and nerves ILLUSTRATIONS & RESOURCES  This gland contains occasional adipocytes These are items youwhich is paste can copy and a feature to make yourfound slides more engaging and interesting in older individuals A –Adipocytes E –Excretory duct S -Septum  Submandibular Gland  Consists of a mixture of serous and mucous secretory units – usually in the form of mixed secretory units.  However, pure serous and pure mucous units are also found.  Mixed secretory units consist of mucous acini with serous demilunes. ILLUSTRATIONS & RESOURCES These are items you can copy and paste to make your slides more engaging and interesting D –Striated duct M –Mucous acini SD –Serous demilune Resources 1. Wheater’s functional histology, sixth edition 2. Netter’s essential histology, third edition  IT’S For any queries or questions A please feel free to contact me: [email protected] WRAP