COMPOSITION, FUNCTIONS AND
PHYSIOLOGICAL ASPECTS OF SALIVA
BY ;-
DR QAZI IMTIAZ RASOOL

1. Describe the secreto-motor nerve supply of the salivary glands
2. Discuss the composition of salivary secretion.
3. Describe the mechanism and regulation of salivary secretion
4. Enumerate the functions of saliva

1. ANATOMY;-
1
.
Major salivary glands
1) Parotid;- 20 grams , serous (20-25%)
2) Submandibular;- 10 gram mixed (70%)
3) Sublingual;-5gram mucus (5-10%)
2.Minor salivary gland
1. Not found in gingiva and anterior part of the hard palate
2.Von Ebner below the sulci of the circumvallate and folliate papillae of the tongue
3.Glands of Blandin-Nuhn: ventral tongue
4.Palatine, glossopalatine glands
5.Weber glands

2. PHYSIOLOGY;-
1.Serous salivary glands
2.Mucous salivary glands
3.Mixed salivary glands
Nerve supply
1. No direct inhibitory innervation
2.
Both parasympathetic (more prevalent) and sympathetic impulses
3. Parasympathetic impulses may occur in isolation, evoke most of the fluid to be excreted, cause exocytosis, induce contraction of myoepithelial cells (sympathetic too) and

Inferior salivary nucleus
Glossopharyngeal nerve
Tympanic branch
Tympanic plexus 9th
Lesser petrosal nerve
Otic ganglion
Lesser petrosal N .
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

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

1.Para-sympathetic Nerve- moderately dilate-blood vessels
3
2. Salivation itself directly dilates B.V,
3.. Also vasodilator effect is caused by kallikrein secreted by activated salivary cells,
2
Acts on α
2
-globulin
Bradykinin (vasodilator).
1

COMPOSITION
97-99.5% water
1-2L/day, (
1ml / gm/ min - 60 times that of pancreas
).
Basal flow rate 0.5→
5mL/min
7.4) pH slightly acidic (pH 5.8 -

Solid Composition 0.5%-1%
1. Inorganic salts (1/3) Na + 40, K + 15, Cl – 25, PO
4
, HCO
3
– 30(mmol/L)
2. Digestive enzyme S .
Amylase, lingual lipase,
3. Proteins – Mucin, Lysozyme, Defensins, and IgA , RNA-ease
Statherins,Proline-richProteins,Histatins, Cystatins,
4. Metabolic wastes – urea , uric acid
5. Hormones – Kallikaren , Lactoferrin , Somatostatin ,Glucogan ,
Lactoperioxidase,
Salivary peroxidase
6. Heavy metalsHg , Pb
7. Nerve growth factors, renin
8. Specific blood groups A,B,O, Le secretors
9. Cellular component Desquameted Ep; cells, WBC,

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

2 stage hypothesis
1. Primary saliva
1. Serous and mucous cells
2. Intercalated ducts
2. Modified saliva
1. Striated and terminal ducts
2. End product is hypotonic

Responses
Effects of Stimulation
Parasympathetic Sympathetic
Saliva output Copious Scant
Response
Sustained Transient
Composition
Response to denervation
Protein poor
↑ K + and HCO
3
↓ secretion atrophy high Protein-rich,
↓ K and HCO
↓ secretion
• -potency of stimuli= sour>salt>sweat>bitter
• Lemon combinig sour+sweet is the strongest
•
Dry>moist, round objects>irregular
3

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

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

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

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

8.ANTI-MICROBIAL ACTIVITIES
Inhibition of bacterial adhesion to tooth surfaces
Inhibition of glucose uptake and acid production
1 . Lysozyme ;derived
1. Major and
2. Minor salivary glands,
3. Phagocytic cells and
4.Gingival crevicular fluid
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

9. PROTEOLYTIC ENZYMES
Thiocyanate and Lactoferrin ions
in entering the bacteria where these ions in turn become bactericidal, and
thus helping further to remove the bacterial metabolic support. protein antibodies that can destroy oral bacteria

– 10 . PROTECTIVE EFFECT
– 1 . keeps the mouth and teeth clean
– 2. Ig A and lysozymes (defense against bacteria)
– 3. HCO
3
prevents dental carries
– 4.Diluting noxious substances and the corrosive HCL+ pepsin
→ esophagus and
.
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
22
5. Sensory analysis by touch,

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

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 centre in brain.
3) Motor pathway (parasympathetic and sympathetic).
1. Conditional Reflex which is developed by habit as follows reflex from higher cortical centres a.By sight b.By smell c.Even by sound d.Thought
2. Unconditional Reflex i.e. , mouth, Oesophagus, stomach, ileum.

( Calculus formation )

Cystatins,
Mucins
Histatins
Amylases, Cystatins,
Histatins, Mucins,
Peroxidases
Anti-
Bacterial
Buffering
Carbonic anhydrases,
Histatins
Amylases,
Mucins, Lipase
Anti-
Viral Digestion
Salivary
Families
Anti-
Fungal
Mineralization
Tissue
Coating
Lubrication &Viscoelasticity
Cystatins,
Histatins, Prolinerich proteins,
Statherins
Amylases,
Cystatins, Mucins,
Proline-rich proteins, Statherins
Mucins, Statherins

1.
The modern day chewing gums are made of four major ingredients including synthetic rubber, plastic, sugar, and coloring (dye).
2.
Instead of telling customers what they are really eating, ‘gum base ’ is used to generalize a list of ingredients that is never published
3.
Most chewing gum is sweetened with aspartame . Long term use of aspartame has been linked with cancer, diabetes, neurological disorders, and birth defects
4.
You are using 8 muscles during chewing, over use of jaw joint causing unnecessary tears in cartilages
5.
Wastage of 6 glands secretions, more intake of sugars, alle rgy