Anatomy and physiology of salivary glands

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Anatomy and physiology of salivary glands

  1. 1. Dr. Supreet Singh Nayyar, AFMCFor more topics, visit www.nayyarENT.com
  2. 2.  Anatomy of Parotid, Submandibular, Sublingual glands Physiology – structure of glands, secretion of primary fluid, neuronal control, neurotransmitters Factors affecting salivary flow & composition www.nayyarENT.com 7/13/2012 2
  3. 3.  3 Pairs – Major salivary glands  Parotid  Submandibular  Sublingual Collection of salivary tissue within oral mucosa – Minor salivary glands www.nayyarENT.com 7/13/2012 3
  4. 4.  Ectoderm of oral cavity Solid bulb from oropharyngeal epithelium  6 weeks - parotid gland Dichotomous branching of solid bulb, development of lumen, condensation of mesenchyme Formation of primitive ducts www.nayyarENT.com 7/13/2012 4
  5. 5.  Engulfment of facial nerve – 16th- 21st wk Functional maturation after feeding is established www.nayyarENT.com 7/13/2012 5
  6. 6.  Lobulated, “inverted pyramid”, extent Superficial, deep lobes Parotid space Borders - ant, post Surfaces – superficial, superior, anteromedial, posteromedial www.nayyarENT.com 7/13/2012 6
  7. 7.  Condensed deep cervical fascia, tough, inelastic surface component, thin deep layer Stylomandibular ligament Fibrous septa arise from capsule Contents of fascia – superficial lymph nodes, greater auricular nerve www.nayyarENT.com 7/13/2012 7
  8. 8. • Facial nerve,division of gland• Retromandibularvein, anterior andposterior divisions• External carotidartery, terminalbranches www.nayyarENT.com 7/13/2012 8
  9. 9.  Capsule – Periparotid Nodes Mostly superficial to Facial Nerve Part of MALT, secrete IgA Salivary gland tissue may be present within the lymph nodes www.nayyarENT.com 7/13/2012 9
  10. 10.  Stylomastoid foramen Methods of identification during surgery  TM Sulcus  PBD  Tragal pointer  Mastoid  Retrograde  Styloid process www.nayyarENT.com 7/13/2012 10
  11. 11.  Varied, Surgically important Single trunk, divides into Zygomaticotemporal, Cervicomandibular Temporal, upper / lower zygomatic, buccal Buccal, cervical, mandibular www.nayyarENT.com 7/13/2012 11
  12. 12.  Type1-5 ( Katz and Catalano, 1987)  Type 1 (25%) – No anastomotic links  Type 2 (14%) – Buccal fuses distally with Zygomatic  Type 3 (44%) – Major communication between Buccal & others  Type 4 (14%) – Anastomosis between major divisions  Type 5 (3%) – More than one Facial Nv trunk Unpredictable preoperatively, to be precisely defined during surgery www.nayyarENT.com 7/13/2012 12
  13. 13. Parasympathetic SympatheticInferior salivatory nucleus Superior cervical ganglion IX nerve Plexus around ECALesser Petrosal nerve PAROTID Otic ganglionAuriculotemporal nerve PAROTID www.nayyarENT.com 7/13/2012 13
  14. 14.  Formed near the anterior border Lies on superficial surface of Masseter Opens in the mouth at parotid papilla Accessory Parotid tissue www.nayyarENT.com 7/13/2012 14
  15. 15.  Development  6th IU wk  Ectoderm in floor of primitive oral cavity  Lateral to primitive tongue  Development of acini – 12th wk Large superficial, small deep lobe Located in Submandibular triangle Well defined capsule www.nayyarENT.com 7/13/2012 15
  16. 16.  Superficial Lobe  Inferior surface – Digastric, Deep fascia, Platysma, Skin  Lateral surface – Submandibular fossa,  Medial surface – Mylohyoid, Facial artery Hyoglossus, Lingual nerve, XII nv, Submandibular ganglion, Deep lingual vein www.nayyarENT.com 7/13/2012 16
  17. 17.  Extends for a variable distance between Mylohyoid & Hyoglossus Relations  Superior – Lingual nerve  Inferior – XII Nv, Deep lingual vein, Submandibular duct www.nayyarENT.com 7/13/2012 17
  18. 18.  5 cm in length Middle of deep part Crosses Sublingual space Proximally – b/w Mylohyoid & Hyoglossus Distally – b/w Genioglossus & Sublingual gland Opening – on sides of frenulum of tongue Relation to Lingual nerve www.nayyarENT.com 7/13/2012 18
  19. 19.  Branches of Facial & Lingual arteries Lymph nodes adjacent to the superficial part www.nayyarENT.com 7/13/2012 19
  20. 20.  Parasympathetic  SympatheticSuperior Salivary Nucleus Superior Cervical Ganglion Nervus Intermedius Plexus around Facial Artery Facial Nerve Chorda Tympani Submandibular Ganglion Lingual Nerve SUBMANDIBULAR GLANDSubmandibular Ganglion www.nayyarENT.com 7/13/2012 20
  21. 21.  Skin incision – 4 cm below Mandible Ligation of Facial vessels above & below Dissected away from Lingual Nerve Lymph nodes in substance of gland www.nayyarENT.com 7/13/2012 21
  22. 22.  Development  8th wk  Epithelial buds present in paralingual sulcus Almond shaped Located in anterior part of floor of mouth www.nayyarENT.com 7/13/2012 22
  23. 23.  Sup – Oral floor mucosa Inf – Mylohyoid Post – Deep part Submandibular gland Med – Lingual nerve, Submandibular duct, Genioglossus Lat– Med surface of lower Mandible www.nayyarENT.com 7/13/2012 23
  24. 24.  Ducts  Multiple  Drain into oral cavity directly or into Submandibular duct Blood supply Nerve supply www.nayyarENT.com 7/13/2012 24
  25. 25. www.nayyarENT.com
  26. 26.  Produce saliva – 1L / day (1ml/min/gm) Contents  Mucin (glycoprotein)  Salivary amylase  Secretory Immunoglobulins  Other enzymes – DNase, RNase, lysozyme, lactoperoxidase, lingual lipase  Kallikerin  Inorganic compounds – Na+, K+, HCO3-, Ca2+ www.nayyarENT.com 7/13/2012 26
  27. 27.  Lubrication and protection Buffering and clearance Maintenance of tooth integrity Antibacterial activity Taste and digestion www.nayyarENT.com 7/13/2012 27
  28. 28.  Parotid  Largest, serous (Compound Tubuloacinar Gland) Submandibular and Sublingual  Mixed (Compound Tubuloacinar Glands) www.nayyarENT.com 7/13/2012 28
  29. 29.  Serous Acini ◦ Pyramid shaped, basal nucleus, apical secretory granules Mucus Acini ◦ Larger, columnar cells, basal nucleus Mixed Acini ◦ Mucus acini capped by serous cells forming Serous Demilunes www.nayyarENT.com 7/13/2012 29
  30. 30. Acini Intercalated Ducts Striated DuctsInterlobular Excretory DuctsStenson’s, Wharton’s duct www.nayyarENT.com 7/13/2012 30
  31. 31.  High rates Rate of saliva production – 1ml/min/gm Blood flow 10 times that of equal mass of skeletal muscle www.nayyarENT.com 7/13/2012 31
  32. 32.  Active transport process under neuronal control Composition  Hypotonic to plasma  Tonicity more when rates of production are high( at max rate - 70% to that of plasma)  K+,HCO3- higher than in plasma  pH – acidic during resting phase, basic during active phase(↑ HCO3- secretion) www.nayyarENT.com 7/13/2012 32
  33. 33.  Acini – Primary Fluid Secretion  Isotonic to plasma, electrolyte composition fairly constant, exocrine protein Excretory ducts – extract Na+, Cl- and add K+, HCO3- to saliva  No addition in volume  More of Na+, Cl- removed than addition of K+, HCO3- responsible for hypotonicity www.nayyarENT.com 7/13/2012 33
  34. 34.  Osmotic process  Transepithelial salt gradients  Four ion transport systems - luminal and basolateral membranes generate the gradient  Three mechanisms proposed – operate concurrently www.nayyarENT.com 7/13/2012 34
  35. 35.  Stimulation – rise in cytosolic Ca2+ Opening of K+, Cl- channels – KCl outflow Cl- conc in lumen ↑, Na+, H2O follow Cl- entry sustained via Na+K+2Cl- cotransporter 6 Cl- translocated to acinar lumen per ATP hydrolysed by Na+/K+ ATPase www.nayyarENT.com 7/13/2012 35
  36. 36.  Cl-/HCO3-, Na+/H+ exchanger KCl outflow Cl- entry via Cl-/HCO3- exchanger Acidification buffered by Na+/H+ exchanger 3 Cl- translocated to lumen per ATP hydrolysed Na+ & water follow into the lumen www.nayyarENT.com 7/13/2012 36
  37. 37.  Involves acinar HCO3- secretion 3 HCO3- secreted per ATP molecule H+ extruded via Na+/H- exchanger Na+, H2O follow into the lumen www.nayyarENT.com 7/13/2012 37
  38. 38.  Contained in zymogen granules present in serous acinar cells, ductal cells Upon stimulation release contents in lumen by exocytosis Conc and rate varies with level and type of stimulation www.nayyarENT.com 7/13/2012 38
  39. 39.  Inconstant, underlying mechanisms partially understood Produce final hypotonic solution Influence of tubular cells more when flow rate is slow www.nayyarENT.com 7/13/2012 39
  40. 40.  Predominant control – PARASYMPATHETIC Sympathetic stimulation shorter and less strong Probable synergistic action www.nayyarENT.com 7/13/2012 40
  41. 41.  Primary fluid secretion Protein secretion Vasodilatation Increased metabolism and growth Myoepithelial cell contractionLARGE VOLUME LOW PROTEIN OUTPUT www.nayyarENT.com 7/13/2012 41
  42. 42.  High protein secretion Vasoconstriction – decreased blood flow Myoepithelial cell contractionLOW VOLUME HIGH PROTEIN OUTPUT www.nayyarENT.com 7/13/2012 42
  43. 43.  Parasympathetic ◦ Ach binds to M3 Receptors ◦ Activation of G protein Phospholipase C IP3 & DAG Intracellular Ca2+ release, Protein exocytosis www.nayyarENT.com 7/13/2012 43
  44. 44.  Sympathetic ◦ Noradrenaline binds to α1, β1 receptors ◦ Activation of G protein Adenylate Cyclase activation ↑cAMP dependant Protein Kinase protein exocytosis www.nayyarENT.com 7/13/2012 44
  45. 45.  Unstimulated – Submandibular Stimulated – Parotid 2/3rd Acidic tastes – Max stimulation Sweet tastes – Least stimulation www.nayyarENT.com 7/13/2012 45
  46. 46.  Psychic factors Circadian rhythm Diurnal variation Age Drugs  Tricyclic antidepressants  Phenothiazines Depression and anxiety states Dehydration, hemorrhage, www.nayyarENT.com 7/13/2012 46
  47. 47.  Salivary Gland diseases  Radiation sialadenitis  Autoimmune sialadenitis  HIV infection  Iron overload  Sarcoidosis  Amyloidosis  Cystic fibrosis www.nayyarENT.com 7/13/2012 47
  48. 48.  Flow rate Source of secretion Type of stimulus Diurnal variation Diet Drugs – flow dependant components Hormones – mineralocorticoids, ovulation www.nayyarENT.com 7/13/2012 48
  49. 49.  Disease states  Sialadenitis  Radiation damage  Sjorgen’s syndrome  Cystic fibrosis  HTN  DM  Alcoholic cirrhosis  Aldosteronism  Chronic pancreatitis www.nayyarENT.com 7/13/2012 49
  50. 50.  Valid medium, painless, non-invasive Hormone monitoring  Unconjugated steroids  Proportional to free unbound plasma levels  Useful in field studies  Estradiol, progesterone, testosterone www.nayyarENT.com 7/13/2012 50
  51. 51.  Drugs  Factors – lipid solubility, protein binding, molecular size, flow rates  Constant saliva / plasma ratio not established Microbial antigens, antibodies  Hepatitis A, B, C  HIV  Immunisation status www.nayyarENT.com 7/13/2012 51
  52. 52.  Tc 99m pertechnitate Scintigraphy – objective measure of its uptake, concenteration, excretion www.nayyarENT.com 7/13/2012 52
  53. 53.  Concentric shells of calcareous material alternating with organic material Stasis of flow Distribution  Submandibular gland – 92%  Parotid – 6%  Sublingual / minor salivary glands – 2% www.nayyarENT.com 7/13/2012 53
  54. 54.  Scott-Brown’s Otolaryngology – 6th ed, Vol 1, Vol 5 Otolaryngology Head & Neck Surgery –Charles W Cummings, 4th ed, Vol 2 Skandalakis’ Surgical Anatomy Last’s Anatomy – 9th ed Physiology – Berne & Levy, 5th ed www.nayyarENT.com 7/13/2012 54

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