Saliva

Question 1

Saliva Functions

Answer 1

Hydration of oral cavity
Lubrication of food
Swallowing, digestion
Aid for optimal function of taste buds
Maintenance of environment rich in Ca2+ and PO4 3- and other buffering agents;
Antibacterial, antiviral, antifungal properties.

Question 2

Saliva by numbers
(How much in the mouth, saliva film thickness, ms, etc)

Answer 2

.5-1 L of saliva
Almost no saliva during sleep
In the mouth: 0.8-1.2 mL
Saliva film thickness: 70 - 100 um
Movement speed: 1-8 mm/min

Question 3

Extrinsic (Major) Salivary Glands

Answer 3

Parotid gland (serous)
Submandibular gland (mixed)
Sublingual gland (mucous)

Secrete saliva on stimulation and account for 90% of the saliva formed.

Question 4

Intrinsic (Minor) Salivary Glands

Answer 4

Buccal glands
labial glands
Palatine glands, etc

Secrete saliva at a constant rate and account for 10% of the saliva formed.

Question 5

Parotid Gland ducts/muscles

Answer 5

Parotid gland -> stensen’s duct. (Serous)

Masseter muscle inbetween.

Question 6

Submandibular gland duct

Answer 6

Wharton’s duct

(Mixed)

Question 7

Sublingual gland ducts

Answer 7

Multiple ducts known as Ducts of Rivinus.

Question 8

Types of Acini Cells:

Serous Secretions

Answer 8

Mostly protein and water
Small amounts of carbohydrates
Zymogen granules (precursors of amylase)

Question 9

Types of Acini Cells:

Mucous Secretions

Answer 9

High in carbohydrates
Mucin (glycoprotein) when mixed with water forms mucous

Question 10

Saliva secretion regulated by what?
Parasympathetic / Sympathetic stimulation

Answer 10

Regulated by autonomous nervous system

Parasympathetic stimulation: water and electrolyte rich saliva

Sympathetic stimulation: viscous and proline rich saliva

Question 11

Parotid gland : nerve

Submandibular / sublingual gland: nerve

Answer 11

Parotid gland: CN IX, glossopharyngeal nerve

Submandibular / Sublingual gland: CN IIV, facial nerve.

Question 12

Pellicle formation process

Answer 12

1.) Enamel made of hydroxyapatite, contains Ca2+ which is positively charged.
2.) Attracts salivary proteins like MUC5B, PRPs, Statherin.
3.) Statherin plays an important role in preventing demineralization.
4.) 1 um thick; base for adhesion or repulsion of bacteria.
5.) Diffusion barrier to dietary acids
6.) Reservoir for Ca2+ and PO4 3-.

Question 13

Lysozyme

Answer 13

From major and minor salivary glands, gingival crevicular fluid, and salivary leucocytes;
§ Muramidase activity: breaks down bacterial cell wall of Gram positive bacteria;
§ Cationic protein: can activate bacterial autolysins.

Question 14

Lactoferrin

Answer 14

Iron-binding glycoprotein

Removes source of iron from bacteria. Antibacterial, antifungal, antiviral.

Iron-binding glycoprotein;
§ Secreted from serous cells of major and minor
salivary glands;
§ Sequesters iron that is required for bacterial growth;
§ Antibacterial, antiviral, and antifungal.

Question 15

Peroxidase

Answer 15

Forms hypothiocyanate which has antimicrobial property.

Salivary gland-derived peroxidase (SP) ;
§ Leucocyte-derived myeloperoxidase (MP);
§ Antibacterial, antiviral, and antifungal. Thiocyanate, filtrate from

Question 16

Histatins

Answer 16

Antibacterial peptide from parotid and submandibular gland;

Histatin 5: kills candida albicans

HIstatin 1 & 2: increases wound healing

Histatin 5: regulates immune response.

Question 17

Agglutinins

Answer 17

Clump bacteria and remove them.

Glycoproteins that clump unattached bacteria;
§ Increases clearance of bacteria;
§ High molecular weight glycoprotein: gp340 (can
clump up to 109 bacteria);
§ MUC5B & MUC7: also clump bacteria and hold
water to lubricate mucosal surfaces.

Question 18

Immunoglobulins

Answer 18

Secretory IgA prevents bacterial adherence to mucous membrane.

There is more IgA in saliva than IgG;
§ Secretory IgA prevents bacterial adherence to
mucous membranes;
§ Increased levels of IgA in high caries rate
populations in response to high levels S. mutans.

Question 19

Cystatins

Answer 19

Cysteine-containing phosphoproteins;
§ Inhibits bacterial proteases;
§ Cystatin S binds to Hydroxyapatite: prevents
precipitation of Ca2+ and PO43- ;
§ Antibacterial and antiviral.

Question 20

Bicarbonate buffer system pH range

Answer 20

Excreted at higher flow rates/stimulated saliva

pH range 5-7

Question 21

Phosphate buffer system

Answer 21

concentration decreases with increasing flow

pH: 6-8

Question 22

Protein buffer system

Answer 22

isoelectric point : pH 5-9.
Major contribution at below pH 5

Sialin = main buffering protein.

Question 23

Challacombe Scale

Answer 23

Mild: 1-3
Moderate: 4-6
Severe: 7-10

Question 24

a-amylase

Answer 24

Serous cells in parotid and submandibular glands;
§ Breaks down long-chain carbohydrates into
maltose, maltotriose, and dextrins;
§ Provides substrate for oral bacteria;
§ Removes starch containing food debris from teeth.