Salivary glands and salvia - Intro Flashcards
what are the 3 major glands?
- Parotid
- Submandibular
- sublingual
Name some minor glands.
lips, cheeks, palate , oropharynx , tongue
What does salvia lack?
- urgency of blood
- endeavour of sweat
- emotion of tears
what salvia does the parotid gland produce?
99% serous
what do serous cell make?
watery salvia
what salvia does the submandibular gland produce?
mixed mucous / serous
what is mucous?
thick viscous salvia with more mucoproteins (glycoproteins)
what salvia does the sublingual gland produce?
largely mucous secretions
what is the function of the salivary gland system characterised by?
the continuous resting secretion upon which intermittently an enormously increased activity is superimposed (i.e feeding)
when is resting secretion present?
throughout the day and night
less in night
what does salvia do to the mouth and oropharynx-pharynx?
keeps it :
- moist
- lubricated
- Protected
how much salvia is produced per day?
500-750ml / day
How much of the salvia produced is from the major and minor glands?
- 90% from major salivary glands
- 10% from minor salivary glands
how much salvia I produced at rest?
0.3ml /min
unstimulated flow rate
how much salvia is produced when stimulated?
1.75ml/min when stimulated
what happens during stimulation?
oral stimulation which triggers reflex response
How much salvia is produced by each gland at rest?
- 10% from parotid
- 70% from submandibular
- 10% from sublingual
- 10% from minor glands
How much salvia is produced by each gland when stimulated?
- 60% from parotid
- 30% from submandibular
- 5% from sublingual
- 5% from minor glands
where does serous salvia come from?
mainly parotid and submandibular glands
where does mucous come from?
mainly from sublingual and minor glands
what is the mixture of all the salvias in the mouth?
whole saliva
where does sublingual salvia flow?
most flows in the “lingual gutter” underneath the tongue on the lingual side of teeth
where does the salvia flow from the parotid , submandibular and minor mucous gland secretions ?
across the tooth
Does salvia cross the midline?
no
What are the functions of salvia ?
- protects tissue
- enhances taste
- lubricates food
- speeds oral clearance of food
- facilitates removal of carbohydrates
- neutralizes organic acids
- inhibits demineralisation / enhances remineralisation
- recycles ingested fluoride to the mouth
- discourages bacterial growth
- proteins sustain enamel surface
What factors influence the stimulated flow rate?
- Mechanical stimuli (unilateral stimulus)
- Age
- Gustatory and olfactory stimuli
- Gland size
- Food intake
- Vomiting
- Visual stimulus
when does salivary glands start to mature?
age 5/6
what is Xerostomia?
Dry mouth
-lack of saliva
when is dry mouth perceived/
when unstimulated flow < 50% normal
What can cause Xerostomia?
-Disease / damage :
>systemic
>local - intrinsic / extrinsic (radiotherapy)
-Medications e.g B- blockers, anti- histamines
-Dehydration
-During sleep
what are the problems with Xerostomia?
-Increased caries
-Mucosal infections esp fungal
-Pain from oral mucosa
-Difficulty:
>chewing
>swallowing
>speaking
-Impaired taste
What is the difference between the normal time for a carious lesion to effect dentine compared to someone with a dry mouth?
Normal - 3 years
Dry mouth- 9 weeks
what is the evidence for increased Xerostomia?
Main evidence - induced by radiotherapy
Increasing evidence - induced by medication or disease
what is the difficulty with evidence of Xerostomia?
- inadequate studies of some types of xerostomia
- something different about radiation-induced xerostomia
what can occur very quickly with Xerostomia?
root caries
How does the composition of salvia vary?
- from gland to gland
- with rate of secretion
- between species
How much of salvia does water make up?
99%
-important in most functions
In addition to water, what else is found in salvia?
- Electrolytes / inorganic constituents
- Formed elements / Organic contituents
what type of solution is salvia?
hypotonic
what cations (electrolytes) are found in salvia?
- Na+
- K+
- Ca++
- Mg++
what anion (electrolytes) are found in salvia?
- Cl-
- HCO3 -
- Phosphates
- Thiocyanate
- SO4–
- F-
- I-
- OH-
Discuss the buffering action of salvia.
- HCO3-
- mainly from majr glands
-concentration increases with flow rate
(as does salivary pH)
-minimises drop in pH around teeth after consumption of sugar/acids therefore
minimises demineralisation of teeth
How does salvia act in the mineralisation of teeth?
-supersaturated with Ca2+ and PO43-
-high flow rates associated with:Ca2+, PO43-, OH- and pH:
>decreased demineralisation of teeth
>increased remineralisation of teeth
>increased calculus formation
-helped by presence of fluoride in salvia
What is the critical pH?
pH at which enamel starts to dissolve
what is the critical pH for adults and kids?
adults - 5.5
kids - 6
Name some organic content of salvia.
- Carbohydrate
- Blood group substances
- Glucose
- Lipids
- Cortisol
what is the first stage of carbohydrate digestion?
salivary amylase breaks down polysaccharides (starch) to disaccharides (maltose)
what happens to salivary amylase in the stomach?
Inactivated by acid in stomach
-significant role in digestion?
what can salivary amylase be important in?
breaking down polysaccharides / starches in plaque /around teeth
where does salivary lipase come from?
lingual minor glands (serous glands of von Ebner)
what is the action of salivary lipase in fat digestion?
significant role (remains active at gastric pH )
Describe mucous glycoproteins (Mucins)?
-Complex molecules: > peptide core > oligosaccharide chains - Lubricate - Coat all oral soft tissues : >prevent drying > provide barrier - Important part of “Pellicle” -Aggregate bacteria - Nourish (some) bacteria
Describe the actions of Statherin.
• Prevent precipitation of Ca2+ & PO43- from saliva:
→ Supersaturation
• good for mineralisation of teeth
→ (Potentially) inhibit remineralisation of teeth but:
(Probably) cannot permeate early carious lesion not major problem
? Prevent calculus formation (not once started?)
What is the role of calcium -binding proteins?
Attach to tooth surface :
- role in pellicle
- role in attaching bacteria
when do proteins release calcium?
If there is an acidic challenge which dissovles enamel, proteins reconfigure themselves and release all there calcium in the zone next to enamel, this means it is much harder to dissolve
calcium. Buffer mechanisms
when pH rises it gets picked up again by proteins
Name antimicrobial actions of salvia.
- Amylase -interferes with bacterial adherence
- Histatins - anti fungal , antibacterial
- Cystatins - inhibit tissue-damaging bacterial enzymes
where Is secretory IgA from?
Mainly from minor glands
what are the constituents of sIgA?
- IgA
- Secretory piece
what is IgA synthesised by?
plasma cells in connective tissue of/around glands
what is the secretory piece added by?
glandular epithelium (provides resistance against enzymatic destruction in mouth
what does sIgA do when directed against specific antigens?
- Provides “local” immunity
- Potential for immunisation against caries +/- IgA via crevicular fluid
Name factors affecting salivary flow rate.
- Presence of food in mouth (chemical /mechincal)
- Thought/smell of food
- time of day
- season
- state of hydration
- body position
- drugs
- age
