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OBJECTIVES Describe the secretomotor nerve supply of the salivary glands Discuss the composition of Salivary secretion. Enumerate the functions of saliva Describe the regulation of salivary secretion Identify clinical applications ( Frey's syndrome, gland infections, calculus formation)

Lesser petrosal N. 9th Inferior salivary nucleus Glossopharyngeal nerve Tympanic branch Tympanic plexus Lesser petrosal nerve Otic ganglion 2-Sympath.Fs. : plexus of nerves around external carotid artery. 3-Sensory Fs. : auriculotemporal N. (branch of mandibular N.) ascends from upper end of parotid gland to supply skin of scalp above auricle + great auricular N.(C2,3)

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Nerve supply : 2-Symp.Fs. : from plexus of nerves around Facial +Lingual arteries. 3-Sensory : lingual N. sup.salivary.N Facial N chorda tympani N lingual N submandibular ganglion lingual N


SECONDARY FACTOR 1..PSN- nerve signals also moderately dilate the B.V 2.. Salivation itself directly dilates B.V, 3.. Also vasodilator effect is caused by kallikrein secreted by the activated salivary cells, Acts on α2-globulin Bradykinin (vasodilator). 1 2 3


COMPOSITION Parotid;- wt(20 gram) -serous (20-25%) Submandibular;- wt(10 gram) mixed (70%) Sublingual;-wt(5gram) mucus(5-10%) Minor salivary glands Labial and buccal salivary glands , Glosso palatine salivary glands , Lingual salivary glands Daily - 97-99.5% water -1-2 L, basal flow rate - 0.5 mL/min → 5mL/min (max.) -pH slightly acidic (pH 5.8 -7.4) -Hypo-osmotic 1.Serous: contains enzyme α-amylase 2. Mucous: contains mucin for lubrication

Chemical composition and functions of saliva : 

Chemical composition and functions of saliva

Solid Composition 0.5%-1% : 

Solid Composition 0.5%-1% Inorganicsalts (1/3) Na+40, K+15, Cl–25, PO4, HCO3–30(mmol/L) Digestive enzyme S.Amylase, lingual lipase, Lysozyme Proteins – Mucin, Lysozyme, Defensins, and IgA , RNA-ease Statherins,Proline-richProteins(PRPs),Histatins, Cystatins, Metabolic wastes – urea,uric acid Hormones -Kallikaren,Lactoferrin,Somatostatin,Glucogan, Lactoperioxidase,Salivary peroxidase Heavy metals- Hg , Pb Nerve growth factors, ------renin Specific blood groups A,B,O, Le secretors Cellular component Desquameted Ep; cells, WBC,

Major salivary components : 

Major salivary components Mucin 1 (MG1) IgA Mucin 2 (MG2) Lactoferrin Peroxidases Amylases Carbonic anhydrases Proline-rich proteins Lysozyme Statherins Histatins 1 10 100 1000 10000 Size (kDa)

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2 stage hypothesis of saliva formation Water & electrolytes Isotonic primary saliva Some proteins electrolytes Na+ Cl- resorbed HCO3+K+ secreted Hypotonic final saliva into mouth

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Effects of Stimulation : 

Effects of Stimulation -potency of stimuli= sour>salt>sweat>bitter Lemon combinig sour+sweet is the strongest Dry>moist, round objects>irregular

Functions of Saliva : 

Functions of Saliva 1. MUCIN FUNCTIONS ( mol ;- amphoteric properties buffering of acid+alkalies) 1. Lubrication Tissue Protective coating for hard and soft tissues i.e, oral cavity and esophagus, and food basically never directly touches the epithelial cells of those tissues 2. Binding mucus binds masticated food into bolus that slides easily through esophagus without inflicting damage to the mucosa. 3. Moistens food 4. Dilutes hot and irritant substances 5. React with bacterial adhesins Mucin-coated bacteria may be unable to attach to surface Bacterial adhesion, thereby blocking them

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2. DIGESTION 1.α-Amylase breaks down starch amylose , amylopectin, Maltose ,glucose into smaller molecules (pH 6.8) -Amylase stops functioning at pH 1.5 (stomach) 2. Lingual Lipase Secreted (von Ebner’s glands of tongue) Hydrolyzes medium- to long-chain triglycerides Important in digestion of milk fat in new-born highly hydrophobic enters fat globules 3. Maltase converts maltose to glucose

3. SOLUBILIZES DRY FOOD in order to be tasted, the molecules in food must be solubilized : 

3. SOLUBILIZES DRY FOOD in order to be tasted, the molecules in food must be solubilized 4. DEHYDRATION Good messenger ,mouth dryness sensation of thirst. 5.PRECIPITATION OR CRYSTALLIZATION 1.Statherins prevent precipitation of CaPO4(TARTAR) 2. Proline-rich Proteins (PRPs) Inhibitors of CaPO4 crystal growth (initially formed enamel )

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7. ANTI-FUNGAL ACTIVITIES 1. Histatins -A group of small histidine-rich proteins Potent inhibitors of Candida albicans growth 2. Cystatins A. inhibitors of cysteine-proteases protective against unwanted proteolysis (bacterial proteases, lysed WBC) B. inhibit proteases in periodontal tissues effect on Ca PO4 precipitation 6. EXCRETORY FUNCTION 1.Certain waste matter such as urea + K+- thiocynate 2. Drugs iodide, pencillin, alcohol 3.Viruses;- Rabies, hepatitis, Mumps. Polio viruses.

8.ANTI-MICROBIAL ACTIVITIES Inhibition of bacterial adhesion to tooth surfaces Inhibition of glucose uptake and acid production 1. Lysozyme ( LZ ) Oral LZ is derived 1. major and 2. minor salivary glands, 3. phagocytic cells and 4.gingival crevicular fluid (GCF) 2. Sialoperoxidase (SP, salivary peroxidase) Readily adsorbed to various surfaces of mouth enamel, salivary sediment, bacteria, dental plaque 3. Myeloperoxidase (MP) From WBC entering via gingival crevice 15-20% of total peroxidase in whole saliva

9. PROTEOLYTIC ENZYMESThiocyanate and Lactoferrin ions : 

9. PROTEOLYTIC ENZYMESThiocyanate and Lactoferrin ions — lysozyme— (a) attack the bacteria, (b) aid the thiocyanate ions in entering the bacteria where these ions in turn become bactericidal, and (c) digest food particles, thus helping further to remove the bacterial metabolic support. protein antibodies that can destroy oral bacteria

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10. PROTECTIVE EFFECT 1. keeps the mouth and teeth clean 2. Ig A and lysozymes (defense against bacteria) 3. HCO3- prevents dental carries 4.Diluting noxious substances and the corrosive HCL+ pepsin → esophagus and mouth during vomitting 22 11. MECHANICAL FUNCTION. 1. For taste sensation , by dissolving them. 2. Assistance in chewing and swallowing(↓ resistance for slippage) 3. It helps for speech 4. It helps for washing away the food particles mouth clean 5. Sensory analysis by touch, temperature,+ taste receptors

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Regulation of Saliva Secretion Cephalic (reflex) phase: few minutes prior to food entry Gastric phase: after food enters the stomach Intestinal phase: a) brief stimulatory effect as partially food enters the duodenum, b) followed by inhibitory effects (enterogastric reflex and enterogastrones)

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Mechanism of Secretion is reflex action---- reflex pathway which will consist of;- 1) Sensory pathway from tongue. ( taste, touch, temperature etc 2) Superior and Inferior Salivary center in brain. 3) Motor pathway (parasympathetic and sympathetic). 1. Conditional Reflex which is developed by habit as follows reflex from higher cortical centres By sight b. By smell c. Even by sound d. Thought 2. Unconditional Reflex i.e. , mouth, L.O, stomach, ileum.

Clinical notes: : 

Clinical notes: 1-Mumps parotid gland infection- - swollen, painful because fascial capsule derived from investing layer of deep cervical fascia is strong and limits the swelling of gland. 2-Frey’s Syndrome : - occurs after penetrating wounds of parotid gland. -It is caused by damage to auriculotemporal & great auricular nerves. -During healing, parasymp.secretory Fs. in auriculotemporal N.

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3. Calculus formation : commmon = submandibular gland : - tense swelling below the body of the mandible, -which is ↑ during a meal and is ↓ in size or absent between meals (diagnostic of the case). Clinically: exam; of floor of mouth, 1.Absence of ejection of saliva from the orifice of duct. 2.Stone can be palpated in the duct,

Non-neoplastic Disorders : 

Non-neoplastic Disorders Reactive conditions Mucoceles and ranulas Irradiation reactions Sialolithiasis Necrotizing sialometaplasia Infectious Nutrition disorders Medication reactions Immunologic disorders

Sjögren syndrome : 

Sjögren syndrome Autoimmune disease ,expression of the CL-HCO3 exchanger is lost in the striated duct cells Women; Xerostomia (dry mouth) Keratoconjunctivitis sicca (dry eyes). Dry, erythematous oral mucosa superficial ulceration and poor dentition. Treatment;- 1. No specific therapy 2. Eyedrops and frequent oral fluid 3. (sialogogues), methylcellulose and sour candy 4. Corticosteroids and immunosuppressants.

Today’ s thought : 

Today’ s thought The modern day chewing gums are made of four major ingredients including synthetic rubber, plastic, sugar, and coloring (dye). Instead of telling customers what they are really eating, ‘gum base’ is used to generalize a list of ingredients that is never published Most chewing gum is sweetened with aspartame. Long term use of aspartame has been linked with cancer, diabetes, neurological disorders, and birth defects You are using 8 muscles during chewing, over use of jaw jiont causeing unnecssary tears in cartilages Wastage of 6 glands secretions, more intake of sugars, allergy

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