1. Salivary secretion Functions of saliva Composition of saliva primary secretion modifications Regulation of salivary secretion roles of the parasympathetics and sympathetics

2. Types of secretions from salivary glands Mucous (goblet cells) lubrication Serous (acinar cells) protection Buffering - bicarbonate Oral hygiene - pH + flow + lysozyme Dilution - high flow rate Antibacterial - lysozyme + antibodies Fl - and Ca 2+ digestion

3. Parotid glands - serous Submandibular glands - mixed Sublingual glands - predominantly mucous Parotid + submandibular = 90% volume

4. acinus Intercalated duct Site of primary secretion Striated duct Excretory duct

5. ATP 2K + 3Na + LUMEN OF ACINUS 3Na + 3K + 5K + 6Cl - Cl -  Ca ++ i Synthetic machinery, enzyme synthesis etc. exocytosis + calmodulin? + + + ? H2OH2O H2OH2O H2OH2O Na + Formation of primary secretion

6. acinus Intercalated duct Site of primary secretion Striated duct Site of Na + & Cl - resorption K + & HCO 3 - secretion Excretory duct Myoepithelial cells Myoepithelial cell contraction expels saliva in acini and ducts Contraction stimulated by parasymp. and symp. activation

7. ATP 2K + 3Na + Cl - HCO 3 - Na + H+H+ K+K+ H+H+ H+H+ H+H+ K+K+ Blood Lumen Modification of primary secretion Duct cell K+K+ K+K+ Cl - Tight junctions do not allow passage of water ATP?

8. 1234 20 40 60 80 100 120 140 160 Concentration (mmol/L) Flow of saliva ml/min Na + HCO 3 - K+K+ Cl - 20 40 60 80 100 120 140 160 0 0 PlasmaSaliva 110 mosmol/l 220 mosmol/l Plasma osmotic pressure 310mosmol/l

9. Control of primary secretion ACh stimulates amylase and K + secretion Acinar intracellular calcium concentration is stimulated by: acetylcholine acting through muscarinic receptors noradrenaline acting through  -adrenergic receptors Control of modification in ducts ACh reduces Na+ & Cl- absorption  -adrenergic agonists increase Na + absorption ACh stimulates HCO 3 - secretion Aldosterone stimulates Na+ absorption

10. Control of blood flow vasoconstriction through sympathetic activation vasodilation through parasympathetic activation release of kallikrein on increased metabolism  activation of plasma bradykinin  vasodilation rate of primary secretion dependent on blood flow Maximum blood flow = 20 x max. skeletal muscle flow

11. parotid sublingual submandibular otic ganglion submand.gang. IX T.P T1-T4 esp T2 sup.cervical gang. sup.saliv.nuc inf.saliv.nuc. Autonomic innervation to the salivary glands VII C.T.

12. Reflex stimulation of salivation S.S.N I.S.N N.S.T IX C.T Taste bud parotid subling Submand

13. Reflex stimulation of salivation Input to salivary centres from: taste buds on tongue and in mouth vomiting centre ?higher centres (sight, smell, thought of food) Inhibition due to: sleep fatigue dehydration fear (adrenal activation)

14. Important features of saliva Always hyposmotic Very large volume secretion for mass of glands Secretion regulated by nervous system NOT hormones Both branches of autonomic STIMULATE secretion

15. Clinical problems with salivary secretion Xerostomia - congenital xerostomia, radiotherapy, Sjogren’s syndrome, dehydration rampant dental caries oral ulceration difficulty in swallowing poor taste sensation Excessive salivary secretion - oral infections/irritations, tumours of mouth or oesophagus, Parkinson’s disease, anxiety