Oral Environment Flashcards
What is the most significant component of the acquired salivary pellicle?
Salivary glycoproteins (mucins)
What are the two different types of salivary mucins?
- Oligomeric mucin glycoprotein (MG1)
- Monomeric mucin glycoprotein (MG2)
What is the main role of proline rich proteins (PRP’s) in the oral microbiome?
Act as strong promoters of bacterial adhesion
which type of proline rich proteins (PRPs) are unique to saliva with a high affinity for hydroxyapatite?
A) basic
B) glycosolated
C) acidic
Acidic
what is the function of slatherin?
Prevents the precipitation of calcium phosphate in saliva, maintaining a high calcium level in saliva available for remineralisation of tooth enamel and high phosphate levels for buffering
What do bound pellicle-attached glucosyltransferases act as?
Binding sites for bacterial adhesion
what immunoglobulins are found in pellicle?
IgA and IgG
What immunoglobulin predominates the pellicle
IgA2
What is the protective role of cystatins in the oral environment?
Protects other salivary proteins from degradation
What cationic peptides, secreted into human saliva by salivary glands, are effective at promoting wound healing?
Histatins
Where is oral lysozyme derived from?
- major and minor salivary glands
- phagocytic cells
- gingival crevicular fluid
What is the scale called used to assess oral dryness?
Challacombe scale
What does a score of 1-3 on the Challacombe scale indicate in terms of dry mouth?
Mild dryness
What does a score of 4-6 on the Challacombe scale indicate in terms of dry mouth?
Moderate dryness
What does a score of 7-10 on the Challacombe scale indicate in terms of dry mouth?
Severe dryness
What are the main clinical signs of dry mouth?
- mucosa attaches to mirror
- lobulated and fissured tongue
- shortening of papillae (smooth tongue)
- glossy appearance of mucosa
-debri adhering to mouth - no saliva in FOM
- Cervical caries
What would be the clinical steps required to take if the score is 1-3 on the Challacombe scale?
Routine check up monitoring
What would be the clinical steps required to take if the score is 4-6 on the Challacombe scale?
Further investigations if cause not clear
What would be the clinical steps required to take if the score is 7-10 on the Challacombe scale?
Cause needs to be determined to exclude Sjogren’s, may need to refer.
What would you advise a patient on management of dry mouth if they are a score of 1-3 on the Challacombe scale?
- may not need treatment
- sugar free chewing gum
- attention to hydration
What would you advise a patient on management of dry mouth if they are a score of 4-6 on the Challacombe scale?
- Sugar free gum or sialogogues
- saliva substitutes
- topical fluoride
What would you advise a patient on management of dry mouth if they are a score of 7-10 on the Challacombe scale?
-saliva substitutes
-topical fluoride
What are examples of local treatment to stimulate salivary flow rate in patients with dry mouth?
- sugar free chewing gum/sweets
- artificial saliva pastilles ( salivix)
- SST (saliva-stimulating tablets)
- xylimelts
What are options for treatment of dry mouth?
Local
Systemic therapy
Carboxmehylcellulose based
Mucin based
Gels
What fluoride treatment could you propose to someone with dry mouth?
- sodium fluoride mouthwash (0.05%)
- sodium fluoride toothpaste (2800 or 5000ppm)
What four components make up the basic unit structure of a salivary gland?
- acini
- intercalated ducts
- striated ducts
- secretory ducts
What is an acini and what is its function?
It is a rounded secretory unit which produces the primary salivary secretion
Do the secretory ducts of a salivary gland get smaller or bigger as we travel from the salivary gland towards the mouth?
Bigger
What type of saliva does the parotid gland produce?
Serous
What type of saliva does the submandibular gland produce?
Serous + mucous
What type of saliva does the sublingual gland primarily produce?
Mucous
What are the three different types of acinus?
- serous acinus
- mucous acinus
- mucous acinus + serous demilune
What is the appearance of serous acinar cells down a microscope?
- looks dark with a prominent basal nuclei
- granular
- stains purple/pink
What is the appearance of mucous acinar cells down a microscope?
- pale cytoplasm
- flattened basal nucleus
- many large mucin granules
Why are mucous acinar cells pale in appearance?
Because contained mucins are lost or most easily stained
What is the appearance of mucous acinar cells + serous demilunes down a microscope?
- mucous acinus capped by serous cells
What group of cells can be found around acini and intercalated ducts?
Myoepithelial cells
What are the two main functions of myoepithelial cells?
- “Squeeze” acinus, assisting secretion
- Regulate duct lumen diameter
What is the structure of intercalated ducts?
- low cuboidal cells
- large central nucleus
What salivary glands DO NOT contain striated ducts within their structure?
Sublingual glands
what is the main function of striated ducts?
Active modification of primary saliva composition
what is the key feature of striated duct structure?
Massive basal membrane folding
what does the basal membrane folding of striated ducts allow for?
Increased surface area for exchange of saliva, allowing for change in its composition
When do pseudo-stratified secretory ducts become stratified?
Near termination where cells merge with stratified squamous oral epithelium in oral cavity
What are the three constituents of saliva?
- water
- electrolytes
- organic components
what are the four mechanisms & control of salivary secretion?
- Initial acinar secretion of H2O and electrolytes
- Ductal modification of primary saliva
- Secretion of organic compounds
- Control of secretory mechanisms
Where does ductal modification occur?
In the striated ducts
In a resting acinar cells, what are the concentrations of sodium and potassium ions inside and outside the cell?
Inside: high potassium, low sodium
Outside: high sodium, low potassium
In an activated acinar cells, what happens to potassium ion concentration?
There is an increase in membrane permeability to potassium ions resulting in an increased potassium concentration in salivary secretion
what facilitates the increase in membrane permeability to potassium ions in an activated acinar cell?
Calcium ion release
What are two results of an increase in basal sodium/potassium ion exchange in activated acinar cells?
- No increase in sodium ions, as they are taken out of the cell
- Chloride and potassium ions move into salivary secretion
What activates basal Na+ K+ Cl- c—transporter?
Increase in extracellular K+
Why is Na+ drawn into the salivary secretion down through between cells?
In order to balance out the charge that has been altered by flow of Cl-
What substance is dragged down an osmotic gradient between activated acinar cells to enter the salivary secretion?
H2O
What are the four changes in composition made to saliva in the striated ducts?
- Conversion from isotonic to a hypotonic solution
- Resorption of Na+ and Cl-
- Secretion of HCO3- and K+
- Becomes dependant upon flow rate
What is the key role of HCO3- (bicarbonate) in salivary secretion?
It neutralises acid
What components make up the primary secretion of saliva?
Na+
K+
Cl-
At rest, are striated duct cells permeable or impermeable to water?
Impermeable
what happens to basal ion pumping once striated duct cells are activated?
It increases resulting in K+ increase and Na+ decrease within the cell
What do compensatory movements to and from the lumen during striated duct cell activity result in in regards to saliva secretion?
An increase in K+ and decrease in Na+ concentration within saliva
What do compensatory movements to and from the lumen during striated duct cell activity result in in regards to Na+ and Cl- flow?
Decrease in both Na+ and Cl- as they flow out of lumen and cell
what substance is Cl- exchanged for in the saliva?
HCO3-
What is the effect of a low flow rate of saliva on striated duct modifications?
- more time for resorption of Na+
- results in very low Na+ in saliva
What is the effect of a high flow rate of saliva on striated duct modifications?
- less time for resorption of Na+
- results in less reduction of Na+ in saliva
What happens to salivary gland activity and HCO3- concentration if flow rate is high?
Gland activity increases, along with increased HCO3- in saliva
What are most of the organic components of saliva secreted by?
Acinar cells
What are the three main steps in formation of organic components of saliva?
- Synthesis of protein in association with ribosomes on the RER (requires ATP)
- Protein transferred to Golgi apparatus
- Glycoproteins packaged into vesicles which fuse with membrane and then discharge contents through exocytosis
what is the predominant type of exocrine secretory mechanism in saliva?
Merocrine
In sympathetic pathways, which axon is long and which axon is short? ( in terms of pre and post ganglionic axons)
Pre-ganglionic axon is short
Post-ganglionic axon is long
In parasympathetic pathways, which axon is long and which axon is short? ( in terms of pre and post ganglionic axons)
Pre-ganglionic axons are long
Post-ganglionic axons are short
In the sympathetic pathway, which transmitter is present at the synapse with the ganglion?
Acetylcholine
In the sympathetic pathway, which transmitter is present once the target tissue is reached?
Noradrenaline
In the parasympathetic pathway, which transmitter is present at the synapse with the ganglion, and the target tissue?
Acetylcholine
what receptors control sympathetic salivary secretion?
Alpha 1 and beta 2 adrenergic receptors
What are the receptors involved in parasympathetic control of salivary secretion?
Muscarinic receptors
What is the antagonist for acetylcholine in parasympathetic control of salivary secretion?
Atropine
What is atropine?
A drug that will cause dry mouth
What does sympathetic control of salivary secretion result in once it reaches target tissue?
- increased exocytosis of organic components
- contraction of myoepithelial cells
- increases production of thick low volume saliva
What is Frey’s syndrome usually a result of?
Parotid surgery where damage to the auriculotempral nerve has occurred
Why is the auriculotemporal nerve important in terms of parasympathetics and sympathetics?
Controls parasympathetics to salivary glands and sympathetics to facial sweat glands
What is Frey’s syndrome characterised by ( which is a consequence of attempted regeneration of damaged auriculotemporal nerve)?
Gustatory sweating
What is gustatory sweating?
Where a stimulation that normally causes salivation, ends up activating sweat glands (e.g. when you eat, your face sweats)
what do sensation to gustatory afferents allow for?
Taste (i.e. sour, salt, sweet, bitter)
Why would you describe saliva flow as Ipsilateral?
For example if you chew on the right side of your mouth, your salivary flow on the right side will increase much more than it does on the left side
What two afferents are involved in reflex salivation?
- gustatory afferents
- mechanoreceptive afferents
Most minor salivary glands are mainly mucous, which minor salivary gland is serous?
Serous glands of von ebner
What is a very important ion for buffering in saliva?
Bicarbonate
If a ground section is stained blue, what is this structure likely to be made of?
Collagen
What is the normal average volume of saliva per day?
500-1000ml/day
What is the volume of saliva produced per minute when flow rate is “unstimulated” (at rest)?
0.3-0.5ml/min
What is the volume of saliva produced per minute when flow rate is “stimulated”?
2.0-4.0ml/min
At rest, which salivary gland is predominantly producing saliva?
Submandibular gland
When stimulated, which salivary gland is predominantly producing saliva?
Parotid gland
what effect does the presence of acid within the oral cavity have on salivary flow?
Massively increases salivary flow
Which salivary gland has been found to have an olfactory reflex associated with and increase in salivary flow?
Submandibular gland
Which salivary gland has NOT been found to have an olfactory reflex associated with and increase in salivary flow?
Parotid gland
What happens to salivary flow at night?
Decreases
What condition is perceived when unstimulated salivary flow is less than 50% normal?
Xerostomia
What are four main causes off xerostomia?
- Disease/damage
- Medications
- Dehydration
- During sleep
What are examples of medications that can cause xerostomia?
- analgesics
- beta blockers
- anti-histamines
What dental problems can arise as a result of xerostomia?
- increased caries
- mucosal infections
- pain from oral mucosa
- difficulty chewing,swallowing or speaking
- impaired taste
what are the three main constituents of saliva?
Water
Electrolytes
Formed elements
What anion in saliva is very important for buffering acids?
Bicarbonate
What is a negative consequence of increase in calcium phosphate during mineralisation of teeth?
Increase in calculus formation
What is the role of salivary amylase?
Breaks down polysaccharides (starch) into disaccharides (maltose)
Which salivary glands produce salivary lipase?
Lingual serous minor glands (glands of von ebner)
what is the role of salivary lipase?
Removal of fat deposits from tastebuds
What are mucins also known as?
Mucous glycoproteins
What are the three main roles of statherins?
- Prevent precipitation of Calcium and phosphate from saliva
- Prevent initial calculus formation
- Prevent mineralisation within salivary glands
What is the role of amylase in the oral cavity?
Interferes with bacterial adherence
what is the role of peroxidase/thiocynate in the oral cavity?
Poisons bacteria
what is the role of lactoferrin in the oral cavity?
Deprives bacteria of iron
what is the role of histatins in the oral cavity?
Antifungal and antibacterial
what is the role of cystatins in the oral cavity?
Inhibit tissue-damaging bacterial enzymes
When demineralisation of tooth substance occurs, how long (in minutes) does it take for pH to drop to its lowest ( most acidic)?
5-10 minutes after consuming sugar
how long does it take for bicarbonate in saliva to buffer pH back above critical pH?
Approx 30-60 mins
What two sugars are associated with highest risk of caries?
Fructose and sucrose
