Saliva Flashcards
what is the daily salivary flow
between 500 and 700 ml
what is meant by the equality of saliva
proportion of serous and mucous
when is mucous secretion greater
during sleep
what can reduce salivary secretion
dehydration
why is it important to consider the entire oral environment when establishing the volume of saliva that is secreted
because certian factors have an impact on this secretion such as if the patient is dehydrated
why is state of hydration different in a clinical setting
air conditioning
what is an example of previous stimulation of saliva
chewing gum
what can radiotherapy do to saliva secretion
lead to patients having low secretion of saliva
how can saliva secretion be used clinically
to protect patients against certain effects like radiotherapy
how can circadium rhythms have an impact on saliva secretion
saliva secretion can be different depending on the time of day and time of year
what is the most important element to consider when looking at saliva secretion
medication
how many different medical treatments can have an effect on salivation
400
which medicines are likely to have an impact on salivation
those associated with control of blood pressure
are salivary gland diseases uncommon
no
what is the composition of saliva
99.5% water, ions, 0.3% proteins
what are the ions present in saliva
sodium
chloride
potassium
bicarbonate
why is bicarbonate an important element for saliva
it is the major buffering system, especially when there is stimulated salivation
what is present in saliva that aids in buffering
bicarbonate
phosphate
proteins
what is the function of protiens in saliva
buffer
what is the pKa of phosphate close to
neutral pH
what happens to saliva secretion during sleep
it decreases
how many pKas does histidine have
three
when are proteins important for controlling secretion
when the pH of plaque is very low
why are calcium and phosphate important elements for the saliva to have
they form hydroxyapatite for remineralisation
what is calculus
mineralised plaque
what is required to form calculus
calcium phosphate
what are examples of activities of enzymes
antibaterial
antifungal
antiviral
what are immunoglobins
antibodies
which immunoglobins are present in saliva
IgG and IgA
what is the function of mucin
wet the food
what is the function of fluoride
form fluorapatite as well as antibacterial functions by controlling acidogenic bacteria by producing acid inside the cell
what does fluoride do to bacteria
makes them less prone to acid
how can thiocyanite be described as
antibacterial
what is the main function of bicarbonate and phosphate
buffering
what are buffers in saliva when it is at high flow
bicarbonate
what are the buffers in saliva when it is at rest flow
phosphates
what are the main buffers in saliva when it is at low pH
proteins
what is the role of bacterial ammonia
buffering plaque acid
what is the second messenger of acetylcholine
calcium
what opens to channels to allow calcium to enter
major force from the acetylcholine
what is saliva secretion driven by
calcium release
what activates amylase in the saliva
chloride
what does amylase hydrolyse
1-4 starch glycosidic links
what is amylase important for
digestion
in which secretions are amylase mostly found
mucosal gland secretions
what is another name for lysozyme
muramidase
what is lysozyme
a non specific defence protein that is present in many secretions like saliva, tears, vaginal mucous. has a defence role. causes lysis of bacterial cells
what is another name for lactoperoxidase
sialoperoxidase
where is lactoperoxidase found
saliva and milk
what does sialoperoxidase get secreted from
both salivary glands and bacteria
what is the function of lactoperoxidase
antimicrobial due to its presence of oxygen
what is the function of cystatins
antimicrobial function
what is the full name for the protein gustin
carbonic anhydrase six
what does gustin contain that is important to note
zinc
how does gustin function in taste
by activating taste buds
what is PDE5
an element that is acted upon when people take drugs like viagra leading to affected taste
how can the effect of gustin be changed
with the use of an erectile dysfunction drug
what is the function of histatins
inhibiting calcium phosphate precipitation which affects remineralisation
antimicrobial
what does immunoglobin come from
plasma cells
what is the immunoglobin that can be secreted by salivary glands
IgA
what is the function of the immunoglobins in the saliva
confer specific immunity against bacteria to be the basis of vaccinated against s mutans
can IgA be recruited upon easily
yes
which immunoglobin loses its ability to produce antibodies quickly
IgA
what is lactoferrin
iron binding protein (binds ferric ion)
why does lactoferrin have an antibacterial effect
because it binds ferric ion which some bacteria need to live
where are the microrganisms that need iron to live found in the mouth
the crevicular fluid
what secretes lipase
von ebner glands
where are the von ebner glands in the mouth
on the tongue
why is lipase in the mouth called lingual lipase
because it is produces by glands found on the tongue
what does lipase do
hydrolyse the triglycerides to assist the digestion of milk
what are mucins
glucoprotiens
what are glucoproteins
proteins with carbohydrate side chains
what do mucins do
they bind to the tooth and epithelial surfaces as well as having a protective role by cushioning the tissues
what is the primary pellicle
coating of saliva caused after teeth are brushed and contains mucins
what happens to mucins as they attach to the primary pellicle of the tooth
they become mucous
what are the bacteria that establish plaque
the bacteria that attach to the pellicle coated by mucin
why is there no cariogenic bacteria present if there are no teeth
no pellicle for them to adhere to
which bacteria can be an issue even if there are not teeth
candida alibicans colonises acrylic but not teeth
why do we swallow mucin full of bacteria
the bacteria are attracted to mucin, which promotes aggregation of bacteria to allow us to get rid of the microorganisms as we swallow
what inhibits calcium phosphate crystals
proline rich proteins
what is the anticalculus effect
the inhibition of the calcium phosphate crystals by the proline rich proteins
what is the function of proline rich proteins
anticalculus
bind to hydroxyapatite to act as a barrier and allow hydroxapatite to resist acid attack and remineralise
which protein regulates bacteria attachment
proline rich proteins
what are statherins
proteins that allow super saturation of calcium and phosphate to have an anticalculus effect
how does the titre of IgG in saliva compare to blood
lower in saliva
what are examples of plasma derived substances found in the saliva
albumins
IgG
hormones
drugs
immunoglobins
why can drugs be detected in the saliva
due to spillover from the blood plasma
what are two controls of saliva secretion
conditioned and unconditioned
describe unconditioned stimuli of saliva secretion
this can be mechanical and chemical. mechanical is associated with the pressure of biting forces of the periodontal ligament and oral mucosa, as well as when chewing - the side we are chewing on produces saliva. chemical is associated with gustation and olfaction
how does gustation lead to salivation
through receptors on our taste buds on the palate epiglottis and tongue dorsum
what is umami
the receptor in our taste buds that recognises glutamin
what is umami similar to
salt
how does olfaction lead to saliva secretion
chemical taste from the epithelium in the nasal cavity can lead to weak salivary stimulus in humans
how is olfaction protective
tells us if food has gone bad
explain conditioned stimuli of saliva secretion
psychic stimuli like when thinking about food and innervation
which innervation can increase saliva flow
post sympathetic and parasympathetic
what are the main salivary proteins
- amylase
- cystain
- gustin
- histatin
- immunoglobins
- lactoferrin
- lactoperoxidase
- lipase
- lysozyme
- mucoproteins
- plasma proteins
- proline rich proteins
- statherins
what does amylase require to function
calcium ions
in which secretions can lysozyme be found
saliva
tears
vaginal mucous
how does lysozyme cause cell lysis
by attacking bonds in bacterial cell walls
what do cystatins inhibit
cysteine proteases
what does gustin activate other than taste buds
PDE 5
what are histatins
histidine rich proteins
which bacteria can histatins inhibit
candida albians
streptococcus mutans
how do immunoglobins enter the saliva
via plasma cells in the salivary glands
what forms the basis of vaccination against streptococcus mutans
immunoglobins
what do lipases hydrolyse
triglycerides
what are the three main functions of mucins
protection
lubrication
component of the primary pellicle
why do mucins promote bacterial aggregation
to make easier clearance of bacteria from the mouth
what are mucins molecular wise
macromolecules
what functions do proline rich proteins perform by binding onto the hydroxyapatite
- act as a diffusion barrier
- decrease mineral loss
- resist acid attack
- allow remineralisation
what is saliva super saturated with
calcium and phosphate
what are examples of proteins found in the saliva from plasma
albumins
what are the different potencies of gustation, in descending order
acid
umami and salt
sweet
bitter
what contributes to the taste of spices
common chemical sense
what mediates common chemical sense
nociceptors in mucous membranes
how do parasympathetic nerves affect salivation
increase both secretion and bloodflow
how do sympathetic nerves affect salivation
increase secretion but decrease blood flow to salivary glands
what is the main constituent of the slime layer covering mucous epithelia around the body
mucins
what are secretory mucins composed of
disulphide linked monomers that contain heavily glycosylated domains interspersed with less glycosylated peptide domains
what are pellicles
protein films covering the enamel and epithelial surfaces
what supplies salivary glands nervously
cholinergic parasympathetic nerve
what evokes the secretion of saliva by acinar cells
binding of acetylcholine that binds to M3 and M1 muscarinic receptors
what tends to evoke greater release of stored proteins from acinar and ductal cells
variable innervation from sympathetic nerves which release noradrenaline
what is responsible for the continuous protection of the tooth surface
salivary mucins and proline rich glycoprotein
what are the early pellicle protins
proline rich proteins and statherin
how do early pellicle proteins promote remineralisation
by attracting calcium ions
what are the well known major salivary glycoproteins
mucins
proline rich glycoprotein
immunoglobins
what are the minor salivary glycoproteins
agglutinin
lactoferrin
cystatins
lysozyme
how can histatin be described
as a cationic antimicrobial peptide
what causes caries
streptococcs mutans
what produces the immunoglobins in the salivary glands
b lymphocytes in the interstitial fluid to be taken up by the acinar cells and ductal cells of the salivary glands
where is proline rich glycoprotein produced
in the parotid gland
what produces cystatins
submandibular and sublingual gland
which gland produces the most agglutinin
parotid
in which glands is lactoferrin produced
the mucous more so than the serous
what produces defensins
salivary glands
epithelial cells
neutrophils
what do salivary immunoglobins belong to
the IgA suubclass to make up about 5-15% of total salivary proteins
where does IgA mainly derive from
the crevicular fluid leaked into the oral cavity
how do immunoglobins defend the mouth
provides a broad system of defence because the entire population of salivary immunoglobins bind the majority of microorganisms present in the saliva.
main property of agglutinin
aggregation of bacteria
main property of LL37
broad spectrium killing of bacteria
what is LL37
cathelicidin
main property of cystatins
protease inhibition
main property of defensins
broad spectrum killing of bacteria
main property of histatins
broad spectrum killing of bacteria
main function of immunoglobin
inactivation and aggregation of bacteria
main function of lactoferrin
growth inhibition
main function of lactoperoxidase
growth inhibition
main function of lysozyme
killing
main function of mucin MG1
proton diffusion barrier in the pellicle
main function of Mucin MG2
aggregation
main function of proline rich glycoprotein
aggregation
main function of proline rich proteins
adherence
main function of statherins
adherence
which salivary proteins function in aggregation of bacteria
agglutinin
mucin mg2
proline rich glycoprotein
immunoglobin
which salivary proteins function in killing bacteria
LL37
defensins
histatins
lysozyme
which salivary proteins function in growth inhibition
lactoferrin
lactoperoxidase
which salivary proteins function in adherence
proline rich proteins and statherin
why do mucins cover the dental surfaces
to lubricate and protect from mechanical wear
how do lysozymes kill bacteria
by hydrolysing the cell wall polysaccharides to make bacteria more vulnerable to lysis
is lactoferrin an enzyme
no
what are the antimicrobial peptides of saliva
histatins
defensins
LL37
which glands secrete histains
parotid and submandibular
what is supragingival calculus
calculus above the gumline
what is subgingival calculus
below the gumline
how is the pellicle formed
salivary proteins selectively adsorb onto the tooth surface to form an acquired pellicle
what is essential for microbial adherence
fimbriae
flagella
what enables some microorgansisms which are incapable of adhering to adhere to the pellicle coated tooth surface
microbial coaggregation and coadhesion
what is the driving foce for plaque mineralisation
supersaturation of saliva and plaque fluid with calcium and phosphate
what can happen once organisms attach to the tooth surface
new genes could be expressed so that mature dental plaque can form and biofilm bacteria can assume increased resistance to antimicrobial agents
what can influence the saturation degree of calcium phosphates
salivary flow rate and plaque pH
which molecules have a key role to play in microbial mineralisation
acid phospholipids and specific proteolipids present in cell membranes
where is the greatest amount of supragingival calculus found
on the mandibular anterior lingual surfaces and the buccal surfaces of anterior maxillary first molars
how is supragingival calculus formed
when plaque absorbs calcium and phosphate from the saliva
how is subgingival calculus formed
absorbed of calcium and phosphate from the crevicular fluid into the plaque
what is present within the enamel pellicle that prevent adherence of oral microorganisms and inhibit their growth
glycoproteins
what is required for the initial mineralisation of plaque and bacteria
calcium phosphate supersaturation
membrane associated components
degradation of nucleation inhibitors
what does calculus formation begin with
deposition of kinetically favoured precursor phases of calcium phosphate
which two salivary ions are the raw materials for dental calculus formaiton
calcium and phosphate
what are the two epithelial cell types that compose mammalian salivary glands
acinar cells and ductal cells
what do the acinar cells do
secrete the salivary fluid as well as most of the salivary proteins
what do the ductal cells do
secrete some proteins and modify the ionic composition of the saliva as they convey it to the mouth
describe how fluid secretion arises in salivary glands
- sodium potassium pump maintains intracellular sodium concentration as low and potassium as high.
- NaKCl cotransporter is a secondary active transport system that transports one sodium, one potassium and two chloride ions into the cell in a tightly coupled fashion.
- in the unstimulated state, intracellular calcium is low and the calcium activated potassium and chlorine cells are closed. when the cell is stimulated by acetylcholine, the intracellular calcium ion concentration rises and these potassium and chlorine channels open.
- this allows potassium chloride to flow out of the cell resulting in an accumulation of chlorine ions and their associated negative electric charge in the acinar lumen.
- sodium then follows chlorine by leaking through tight junctions between cells to preserve electroneutrality
- the resulting osmotic gradient for sodium chloride causes transepithelial movement of water from interstitial space to the lumen.
what is saliva initially formed as
a near isotonic plasma like primary secretion in the acinar lumen
describe the changes saliva goes through during secretion
- first formed as a near isotonic plasma like secretion
- salivary ducts modify this primary fluid by removing sodium and chloride and adding potassium and bicarbonate
- final hypotonic solution is what enters the mouth
what is exocytosis
the process by which cells release the contents of their secretory granules, which involves the fusion of the granule membrane with the luminal plasma membrane of the secretory cell following by rupture of the fused membranes.
what controls the exocytic secretion in the major salivary glands
autonomic nervous system - sympathetic stimulation elicits protein release from the parotid and submandibular gland acini, and parasympathetic stimulation elicits protien release from the sublingual gland acini as well as some release from the parotid acini
when is salivary protein secretion evoked
when neurotransmitters bind to specific receptors on the basolateral membrane of the secretory cells and generate intracellular second messengers that in turn activate the cellular mechanisms responsible for secretion
where are the acinar cells found in salivary galnds
in the end pieces of the salivary gland ductal tree
which innervation evokes greater release of stored proteins from acinar and ductal cells
sympathetic nerves releasing noradrenaline
what does the secretory endpiece of salivary glands consist of
aciner secretory units made up of acinar cells which are responsible for synthesising and secreting most of the functionally important protein components of saliva
is salivary gland secretion a reflex
yes
what do the major salivary glands develop from
the ectoderm
what do the minor salivary glands develop from
the mesoderm
what happens in genetic syndrome salivary gland agenesis
absence of ectodermal derived structures like sweat glands and the major salivary glands
what are the clinical symptoms of decreased salivation
oral pain
increased dental caries
infections by opportunist microorganisms like candida albicans
what is salivary gland dysfunction observed as
a consequence of iatrogenic treatments like medications or radiation therapy for head and neck cancers
can also be observed in diseases like cystic fibrosis
what is sjogrens disease
an autoimmune disease in which salivary glands are destroyed by lymphocytic infiltration
which salivary proteins control calcium phosphate homeostasis
statherin and proline rich protein
