Saliva Flashcards
How is saliva produced?
By exocrine glands
What is the ionic composition of saliva?
It is hypotonic
What are the protective functions of saliva?
lubrication, hydration, maintains pH, prevents demineralisation, host defences, clearance, solubilises
What are examples of lubrication & hydration?
mucin and H2O
What are benefits of lubrication and hydration?
Food can be swallowed without damaging tissues
What are examples of maintaining pH?
Buffering
What are examples of preventing demineralisation?
Ca2+ intake and fluroide
What are examples of host defences?
saliva flow
What is clearance?
mucin and water clearing unwanted foreign objects or microbes
What are benefits of solubilising
Food can then be sensed by taste buds
What are defensive functions of saliva?
antimicrobial proteins e.g lactoferrin
What is an example of enzymatic defences?
amylase (starch) and lipase
How much Ca2+ is ionised at the pH of 6.5?
50%
How much salivary calcium is non-ionised phosphate and bicarbonate salts?
30%
How much salivary calcium is bound to other small molecules?
less than 10%
How much salivary calcium is bound to specific calcium-binding macromolecules to prevent precipitation?
10-30%
What macromolecules to salivary calcium bound to?
Histidine-rich proteins, Proline-rich proteins, Statherin
Where is calcium concentrated in the mouth?
In the acquired pellicle
What is pellicle?
the foundation where bacteria and microbes attach
What happens if there’s a drop in pH of saliva?
the ionisation of salivary calcium is lessening demineralisation from hydroxyapatites
What causes dental erosion?
Citrate which is a chelating agent that binds divalent cations such as Ca2+, thus removing Ca2+ from ionic equilibrium
What is the Stephan Curve?
A series of experiments, which is finding what happens to pH when consuming different sugars
What is considered a critical pH?
5.5 pH
How is pH lowered in the mouth?
CO2 converts into carbonic acid and sugars fermented by bacteria
What does buffering mean?
Trying to maintain pH at a constant rate without dropping too much
What are the functions of buffering capacity of saliva?
Restoring the pH after carbohydrate intake, and enhances remineralisation of hydroxyapatites
What causes buffering?
bicarbonates
What are lactoperoxidase?
Enzymes that generate hypothiocyanite anion
What is hypothiocyanite highly reactive with?
sulphydryl groups of proteins
What is the function of lactoferrin?
secrets iron-binding protein
What are the characteristics of lactoferrin?
very high affinity for iron, and are bacteriostatic due to iron with-holding which starves bacteria of iron
What does dilution of substances influence?
Pathogenic processes, pharmacology, normal saliva flow rate, hyposalivation
What is hyposalivation? (xerostomia)
reduced salivary flow
What problems can hyposalivation cause?
Difficulty in talking, eating and wearing dentures, loss of taste, pain, high susceptibility to dental caries
What are causes of Salivary Gland Hypofunction?
Medication induced xerostomia, severe immune deficiency, menopause, eating disorders
What is Sjögren’s Syndrome?
Autoimmune exocrinopathy resulting in hyposalvation
What are three measurable factors that influence caries susceptibility?
Saliva buffering capacity, saliva flow rate, salivary concentration of mutans streptococci
