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Salivary Glands By DMD Students 3rd year
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- 2. FUNCTIONS OF SALIVA 1.Protection 2. Buffering 3. Maintenance of tooth integrity 4. Digestion 5. Defense(antimicrobial action) 6. Taste 7. Tissue Repair
- 3. 1.PROTECTION Washing action: (1)removal of bacteria, toxins, and debris (2) decrease action of acidogenic bacteria Salivary pellicle (protein receptors) Lubrication
- 4. 2. BUFFERING Bicarbonate Phosphate
- 5. 3. TOOTH INTEGRITY Post-eruptive enamel maturation Repair, remineralization → Calcium, Phosphorus
- 6. 4. DIGESTION Bolusformation Digestion of starch into glucose → amylase
- 7. 5. DEFENSE (Bacteriostatic) Mucins Amylase Lysozyme Lactoferrin Peroxidase Immunoglobulins
- 8. 6. TASTE Transportof taste substances Protection of taste receptor Solvent
- 9. 6. TISSUE REPAIR Epithelial regeneration → growth factors Wound healing
- 10. STRUCTURE OF SALIVARYGLANDS Salivary glands consist of -series of branched ducts -terminating in spherical or tubular secretory end pieces or acini Analogy: Bunch of Grapes Stems- ducts Grapes- secretory end pieces
- 11. STRUCTURE OF SALIVARYGLANDS Each gland is divided into lobes and lobules by means of connective tissue septa 1. Intercalated ducts (smallest) (intralobular) 2. Striated ducts (intralobular) 3. Excretory ducts (interlobular)
- 12. STRUCTURE OF SALIVARYGLANDS The basic functional unit of salivary gland is terminal secretory unit called – acini -Serous cells -Mucous cells -Myoepithelial cells Central lumen- star shaped Ductal system Mucous acini > Serous acini
- 13. SECRETORY CELLS 1. SEROUSCELLS Spherical form, narrow lumen Rich in zymogen granules More protein rich than mucous Synthesis, secretion and storage of proteins and glycoproteins
- 14. SECRETORY CELLS 2. MUCOUSCELLS Tubular and/or polygonal configuration with a larger central lumen More carbohydrate rich than protein Synthesis, secretion and storage of mucin
- 15. SECRETORY CELLS 3. MUCOSEROUSCELLS Serous + Mucous Serous Demilunes of Gianuzzi
- 16. Secretory cells releasetheir thin, watery secretions into a small lumen in the center of the acinus. From there, the fluid drains into intercalated ducts, then intralobular ducts that anastomose to form larger interlobular ducts located in the surrounding connective tissue
- 17. DUCTS 1. INTERCALATED DUCTS Lined by single layer of cuboidal cells with a relatively clear appearing cytoplasm In Electron Microscopic studies, the intercalated duct cells resemble serous cells.
- 18. DUCTS 1. INTERCALATED DUCTS Functions: 1. They modify saliva through secretory and resorptive processes. They contribute to substances like lactoferrin. 2. Intercalated ducts also houses undifferentiated cells which can undergo differentiation and replace damage cells in the end pieces or striated ducts.
- 19. DUCTS 2. STRIATED DUCTS Lined by tall columnar epithelial cells with centrally placed nuclei. The cytoplasm is eosinophilic and show prominent striations at the basal end of the cells, perpendicular to basal surface.
- 20. DUCTS 2. STRIATED DUCTS EMstudies: basal cytoplasm of the striated duct cells show deep infoldings of the plasma membrane and many large mitochondria usually radially oriented are located between the infoldings indicating that the cell is involved in active transport.
- 21. DUCTS 2. STRIATED DUCTS Functions: 1. These are site of absorption of sodium, chloride and excretion of potassium and bicarbonate.
- 22. DUCTS 3. EXCRETORY DUCTS As the excretory duct enlarges it contains two layers: o Mucosa o Connective tissue adventitia Does not modify salivary secretion
- 23. DUCTS 3. EXCRETORY DUCTS The Mucosal epithelium is of pseudostratified columnar epithelium occasionally goblet and ciliated cells are seen. The Ductal epithelium slowly undergoes transformation to cuboidal and finally to stratified squamous epithelium
- 24. GENERAL SECRETION OFSALIVA Sodium and potassium ions are equivalent Iodide ions are present at an increased concentration Chloride ions are present at a decreased concentration Bicarbonate is present at the same concentration
- 25. DUCTAL MODIFICATION OF SALIVA Sodium concentration decreases Potassium concentration increases Bicarbonate concentration decreases at rest and increases when stimulated
- 26. DUCTAL MODIFICATION OF SALIVA Restingsaliva Low volume Very hypotonic Neutral or slightly acidic Few enzymes
- 27. DUCTAL MODIFICATION OF SALIVA Stimulatedsaliva High volume Less hypotonic than resting saliva Alkaline Many enzymes
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- 29. Parotid Gland Largestgland From zygomatic process to the angle of the mandible Watery saliva Stensen’s duct CNIX
- 30. Submandibular Gland Submandibulartriangle, below mylohyoid ms. near the inner surface of the angle of the mandible Mixed predominantly serous Wharton’s duct CNVII
- 31. Sublingual Gland Beneaththe submucosa of the anterior part of the floor of the mouth Above mylohyoid ms. Mixed but predominantly mucous Bartholin’s duct CNVII
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- 33. LABIAL & BUCCALPALATINE ANTERIOR LINGUAL POSTERIOR LINGUAL Glands of root of tongue POSTERIOR LINGUAL Glands of Von Ebner Location LIPS AND CHEEKS POSTERO-LATERAL ZONE OF HARD PALATE AND SUBMUCOSA OF SOFT PALATE NEAR THE TIP OF THE TONGUE - - Duct Opening SURFACE OF LIPS AND CHEEKS - VENTRAL SURFACE OF THE TONGUE DORSAL SURFACE OF TONGUE CANAL SURROUNDING CIRCUMVALLATE PAPILLA Nature MIXED BUT PREDOMINANTLY MUCOUS PURELY MUCOUS MIXED BUT PREDOMINANTL Y MUCOUS PURELY MUCOUS PURELY SEROUS
- 34. SALIVARY GLANDS MAJOR SALIVARYGLAND 1. Large glands extraorally located & is bilateral 2. Contains three general structure of salivary gland: Secretory cell, duct system, connective tissue capsule MINOR SALIVARY GLAND 1. Small group secretory cell 2. Just beneath oral epithelium at submucosa level 3. No duct system but have short ducts 4. No connective tissue capsule 5. Have secretory cell 6. Named according to location in the oral cavity
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- 36. Superior cervicalganglion -Decreased production of saliva by acinar cells -Increased protein secretion -Decreased blood flow to the glands 1. Sympathetic Innervation
- 37. Facial andGlossopharyngeal nerve -Acinar cells increase secretion of saliva -Duct cells increase HCO3 secretion -Co-transmitters result in increased blood flow to the salivary glands -Contraction of myoepithelium to increase the rate of expulsion of saliva 1. Parasympathetic Innervation
- 39. 1. Smell +Taste activate higher centers of the brain 2. Cause salivary nucleus to activate parasympathetic nerves that release Ach which acts at muscarinic receptors to increase saliva secretion (low protein, high fluid volume) Superior salivatory nucleus -> facial nerve -> Submandibular & sublingual Inferior salivatory nucleus -> glossopharyngeal nerve -> parotid gland 3. Sympathetic nerves release NE which act at B adrenergic receptor to increase saliva secretion (protein rich, low volume) ***Saliva secretion starts when neurotransmitters are attached on the cell surface receptors of the acinar cells. Acinar cells contain numerous receptors capable of reacting with several neurotransmitters. The vast majority of acinar cells possess cholinergic (muscarinic) receptors. The neurotransmittory substance is acetylcholine, which acts on the cholinergic or muscarinic receptors. Norepinephrine acts as a postganglial sympathetic neurotransmitter.
- 40. WHAT ARE THE FACTORSAFFECTING SALIVARY FLOW?
- 41. FACTORS AFFECTING SALIVARYFLOW 1. Food
- 42. FACTORS AFFECTING SALIVARYFLOW 2. Anesthetization of the oral mucosa
- 43. FACTORS AFFECTING SALIVARYFLOW 3. Mastication
- 44. FACTORS AFFECTING SALIVARYFLOW 4. The sort and the flavor of the food
- 45. FACTORS AFFECTING SALIVARYFLOW 5. Water
- 46. FACTORS AFFECTING SALIVARYFLOW 6. Age
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