Saliva Flashcards
briefly explain the journey of saliva secretion
starts in the acini (primary secretion)
this secretion travels along the intercalated ducts
these intercalated ducts feed into the straited ducts
the saliva goes onto the secretory ducts
enters the oral cavity
where is the initial salivary secretion made?
acini
which salivary ducts modify the saliva?
striated ducts
why do the striated ducts modify saliva?
they have folded basal membranes
as you get closer to the mouth, the walls of the cells become more stratified, due to multiple layers of the cells lining the wall, true or false?
true
what shape is the central lumen?
ball shaped
what are the 3 types of secretion you can get?
serous
mucous
serous demulines (serous cells around mucus acinar)
what are the physical features of serous acinus?
clearly seen nucleus
nucleus is quite large
what are the physical features of mucous acinus?
has a basal nucleus squashed down to the basal aspect of the cell
are serous acinar cells purple/pink or pale down a microscope?
purple/pink
why do serous acinar cells stain purple?
due to their basophilic rough endoplasmic reticulum
are mucous acinar cells purple/pink or pale down a microscope?
pale
what is attached to the surroundings of acini and intercalated ducts?
myoepithelial cells
what is the function of myoepithelial cells?
can help push the saliva down the ducts faster
what is the physical features of intercalated ducts?
cuboid shape
large central nucleus
intercalated ducts are passive, true or false?
true
do intercalated ducts modify saliva?
no
How striated ducts change the composition of saliva depends on what?
the rate of flow through the salivary gland
if saliva flows through these ducts quickly, will there be more or less change?
more
why do striated ducts have a central nucleus?
massive basal membrane folding
within the basal folds, what are present which explain why the cell is very active with membrane pumps and exchanges?
mitochondria
what are secretory ducts also referred to?
collecting ducts
what ducts empty into the secretory ducts?
striated ducts
which ducts are the largest in diameter?
secretory
what does the secretory ducts eventually merge with?
stratified squamous oral epithelium
what are the main constituents of saliva?
water
electrolytes
organic components
what are the main electrolytes making up saliva?
sodium potassium chloride
bicarbonate
when an acinar cell is in its resting period is the concentration of sodium outside the cell low or high?
high
when an acinar cell is in its resting period is the concentration of potassium outside the cell low or high?
low
when an acinar cell is in its resting period is the concentration of sodium inside the cell low or high?
low
when an acinar cell is in its resting period is the concentration of potassium inside the cell low or high?
high
when a nerve comes along and activate the cell this causes what?
an increase in the membrane permeability to potassium
potassium leaks out the acinar cell because there is too much of it, where does it go?
into the lumen and the connective tissue
what does the co transporter consist of?
sodium
potassium
chlorine
what triggers the co transporter?
the increase in extracellular potassium
what is the purpose of basal sodium and potassium pumps?
pumps sodium out the cell and potassium in at the same time
to maintain the contents of the lumen and ensure they are the same in the connective tissue
the sodium that is pumped in by the co transporter is removed by what?
basal sodium and potassium pumps
an opening of chloride channels allows what?
the increase. of chloride ion to flow out
what attracts sodium into the acinar cell and why?
chloride- drawn into secretion to balance charge
why is water dragged down the osmotic gradient between the acinar cells?
to address the osmotic imbalance
what does isotonic mean?
same concentration as tissue fluid
what does hypotonic mean?
less concentrated solution
in ductal modification, is there a conversion from isotonic to a hypotonic solution or from hypotonic to an isotonic solution?
isotonic to hypotonic
what is an key salivary component that neutralises acid?
bicarbonates
in what duct does bicarbonate secretion take place?
striated duct
in what duct does ductal modification take place?
striated duct
what is in in the single striated duct cells that modify salivary constituents?
they have a folded membrane, its these folds that do the modification
at rest is the striated duct cell permeable or impermeable to water?
impermeable
Inside the cells we have low potassium, low sodium and low chloride, true of false?
false
we have high potassium, low sodium and low chloride
outside the cell we have high sodium, high potassium and high chloride, true or false?
false
we have high sodium, low potassium and high chloride
is there more sodium potassium pumps in the acinar cells or the striated cells
striated because these cells work harder to modify saliva
what are the compensatory movements from the lumen in the striated duct cells?
As sodium is taken out the cell, sodium correspondingly is dragged out of the secretion
Similarly as potassium is added to the striated ducts through the permeability of the membrane, its pushed in
what is the result of an activated striated duct cell?
The result is as the saliva flows through the striated ducts we get an increase in potassium concentration and a decrease in sodium concentration and also a decrease in chloride as the chloride follows the sodium out
what is a chloride bicarbonate exchanger?
an active pump that exchanges chloride for bicarbonate, actively adding bicarbonate to the secretion and removes chloride
what is the known buffering component of saliva and why?
bicarbonate- it counteracts ph changes
what effects the concentration of saliva?
the speed it travels through the ducts
if the saliva flows through the ducts slowly what does this result in?
more time for sodium to be reabsorbed, resulting in low concentrations of saliva
if the saliva flows through the ducts fast what does this result in?
less time for reabsorption of sodium, less reduction of sodium, higher concentration in saliva
when is bicarbonate added into the saliva
in the striated ducts
if the flow rate is high and the gland activity is high, will the bicarbonate pump work more or less?
more - harder
the greater the activity and flow rate, the more:
Bicarbonate
Sodium
Chloride
The greater the activity and flow rate, the less:
Potassium
where are most organic components secreted?
in the acinar cells
what is exocytosis
fusion of secretory vesicles with the plasma membrane and results in the discharge of vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane
what are the 3 types of exocrine secretory mechanism?
merocrine
apocrine
holocrine
the autonomic nervous system consists of 2 branches, what are they?
sympathetic
parasympathetic
what do the sympathetic and parasympathetic divisions of the ANS work in opposing fashion to maintain?
Homeostasis
what is the parasympathetic division of the ANS responsible for?
coordinates the body’s basic homeostatic functions
what is the sympathetic division of the ANS responsible for?
coordinates the body’s response to stress, associated with fight, flight and fright reactions
Where are the neurons from the are involved in the sympathetic division of the ANS
From the spinal cord from T1-l2
what are examples of sympathetic stimulation?
pupils dilate
heart rate increases
blood pressure increases
blood glucose increases
bronchioles dilate
sweat
what neurons are activated from parasympathetic divisIon of the ANS
From the brain stem and further down S2-S4
What is sympathetic also known as?
fight or flight
what is para sympathetic also known as?
rest and digest
what are examples of a parasympathetic stimulation?
pupils constrict
heart rate decreases
glands secrete
GI motility of faeces
Elimination of urine
what are the 2 types of neurons involved in the autonomic pathway
pre-ganglionic
post-ganglionic
Fill in the blanks…
Sympathetic exit the … and they synapse with the … nerve.
This … nerve innovates the target tissue
This … and that … is very … the spinal cord so they have a … post-ganglionic axon
Conversely the … exits the nervous system and a … pre-ganglionic axon and a … post-ganglionic axon
CNS
postganglionic nerve
postganglionic nerve
synapse
ganglion
close
long
parasympathetic
long
long
what is a ganglion?
collection of nerve cell bodies in the periphery
where does the pre-ganglionic neuron originate?
brain or spinal cord
where doe the post-ganglionic neuron originate?
in the ganglion
what is the synapse at the sympathetic nerve at the ganglion in the autonomic pathway?
acetylcholine
what does acetylcholine at the target tissue release?
either noradrenaline or acetylcholine
what is the parasympathetic transmitter?
acetylocholine
is salivary control parasympathetic
sympathetic
or both
both - they cause different types of secretion
Fill in the blanks…
When you are stressed you think you have a dry mouth, you don’t have a dry mouth you just have a different type of secretion. The … produce a viscous, low volume secretion, whereas the … produce a very fluid, watery, high-volume secretion
sympathetic
parasympathetic
what nerves supply or carry the parasympathetic feed to the salivary glands?
facial nerve
glossopharyngeal nerve
Fill in the blanks…
The … nerve carries … axons from the … and takes them to the … in the … (Otics ganglion and remak’s ganglion) that then has a … post ganglionic nerve to the lingual glands and the parotid gland
glossopharyngeal
parasympathetic
inferior salivary nuclei
ganglia
periphery
short
Fill in the blanks…
The … nerve takes feed from the … that takes fibres from the … and they travel and synapse in the … and …. The … ganglion gives … post-ganglionic axons to the sublingual and submandibular glands and the … ganglion gives … post-ganglionic axons to the palatal glands
facial
facial nucleus
superior salivary nucleus
submandibular ganglion
pterygopalatine ganglion
submandibular
short
ptergopalatine
short
what receptor does acetylcholine bind to?
muscaranic
what known antagonist can give a patient a dry mouth?
atropine
what is the target transmitter of sympathetic control salivary secretion?
noradrenaline
what is frey’s syndrome?
a rare, neurological disorder that causes a person to sweat excessively while eating. It most often occurs as a complication of surgery involving the parotid gland (a major salivary gland located below the ear).
what are the 3 pairs of major salivary glands?
parotid
submandibular
siblingual
what type of cells do parotid glands secrete?
serous
what type of cells do submandibular glands secrete?
mixed : serous (80%) and mucous (20%)
serous demilunes
what type of cells do sublingual glands secrete?
mucous
what type of cells do minor glands secrete?
mucous
except serous glands of von ebner
what are von ebner glands?
also known as serous glands, they are minor salivary glands located on both sides of your oral cavity toward the back of your tongue.
at rest where provides the greatest source of saliva and where provides the least?
70% submandibular
10% parotid
10% sublingual
10% minor
when stimulated where provides the greatest source of saliva and where provides the least?
60% parotid
30% submandibular
5% sublingual
5% minor
what is whole saliva?
mix of serous and mucous
where is serous mainly secreted from?
parotid and submandibular
where is mucous mainly secreted from?
sublingual and minor
what are the functions of saliva?
protects tissue
enhances taste
lubricates food
speeds up oral clearance of food
facilitates removal of carbohydrates
neutralises organic acids
inhibits demineralisation
enhances remineralisation
recycles ingested fluoride to the mouth
discourages microbial growth
proteins sustain enamel surface
how does saliva enhance taste?
provides chemicals which food dissolves in
how does saliva enhance remineralisation?
because it is super saturated with calcium and phosphate
how does saliva recycle ingested fluoride to the mouth?
fluoride can be ingested and secreted out through saliva
factors effecting salivary flow rate
presence of food in mouth
smell of food
time of day
state of hydration
drugs
age
size of gland
how does the presence of lots of calcium and phosphate protect the teeth?
they can encourage growth of hydroxyapatite crystals
what is the negative aspect of having too much calcium and phosphate in saliva?
can cause mineralisation of plaque
what are the antimicrobial actions of saliva?
water - cleansing
mucins - aggregation of bacteria
amylase - interferes with bacterial adherence
lysozyme - hydrolyses some bacterial cell walls
peroxidase/thiocyanate - poisons bacteria
lactoferrin - deprives bacteria of iron
histatins - antifungal and antibacterial
cystatins - inhibit tissue damaging bacterial enzymes
what are the 2 main types of salivary gland developmental anomolies?
aplasia
atresia
what is aplasia?
(failure to develop normally)
may occur as an isolated event or as part of a hereditary syndrome (down syndrome)
what is atresia?
(failure to be tubular)
submandibular duct most often affected when it occurs
what is a salivary mucocoele?
a cystic cavity filled with mucus
what are the 2 types of mucocoele?
extravasation
retention
what does statherin prevent?
prevents precipitation of calcium phosphate from saliva
prevents calculus formation
prevents mineralisation within salivary glands
what glycoprotein plays the role in lubrication of all soft tissues to prevent drying and provide a barrier?
mucous glycoproteins (mucins)
what organic content of saliva is part of the 1st stage of fat digestion, cleaning the tastebuds, removing fat deposits?
salivary lipase
what type of salivary glands release salivary lipase?
lingual minor glands serous glands of von ebner
what organic compound is involved in the break down of polysaccharides- having a cleansing effect of saliva?
salivary amylase
other than bicarbonate, what other types of buffers are present in saliva?
protein buffers
phosphate buffers (more organic)
what are the 2 main categories of electrolytes present in saliva?
cations
anions
what are the cations present in saliva?
sodium
potassium
calcium
magnesium
what are the anions present in saliva?
chloride
bicarbonate
phosphate
thiocyanate
sulphate
fluoride
iodide
hydroxyl
what is xerostomia?
the sensation of oral dryness, which can result from diminished saliva production
what is the main clinical difference between mucous extravasation cyst and mucous retention cyst?
mucous retention cyst is rare on lower lip where as extravasation cyst most commonly effect the minor glands in the lower lip
mucous retention effects both minor and major glands whereas extravasation more commonly just effects minor
what is the treatment for a mucocoele?
excision
what is a ranula?
a fluid collection or cyst that forms in the mouth under the tongue
what is the treatment for a ranula?
drainage of the cystic cavity and removal of sublingual gland
what is sialadenitis?
A salivary gland infection is also called sialadenitis and is caused by bacteria or viruses
what are the 2 types of sialadenitis?
acute
chronic
what is salivary calculi (sialoliths/stones)?
Salivary gland stones are calcifications in the salivary gland or in the tubes (ducts) that drain the salivary glands. They create a blockage that obstructs the flow of saliva. Salivary gland stones are the most common cause of inflammatory salivary gland disease.
what is an example of viral sialadenitis?
mumps
how is mumps spread?
saliva
what is nercrotising sialometaplasia?
a benign, self-limiting inflammatory reaction of salivary gland tissue which may mimic squamous cell carcinoma or mucoepidermoid carcinoma, both clinically and histologically
how does necrotising sialometaplasia present clinically?
deep ulcer on the hard palate
what is sjogren’s syndrome?
an autoimmune disease characterised by lymphotic infiltration and acinar destruction of lacrimal and salivary glands
what are the 2 forms of sjogren’s syndrome?
primary
secondary
what is primary sjogren’s syndrome?
patients have dry eyes and/or a dry mouth with no associated connective tissue disease
what is secondary sjogren’s syndrome?
patients have dry eyes and/or a dry mouth and a connective tissue disease. e.g rheumatoid arthritis
are males or females more at risk of sjogren’s disease?
females
what do patient’s with primary sjogren’s syndrome have an increased risk of developing?
lymphoma in affected glands
what is sialadenosis?
non-inflammatory, non-neoplastic, bilateral, symmetrical swelling of salivary glands
where does the majority of salivary gland tumours occur?
parotid gland
what classification is used when diagnosing tumours of salivary glands?
WHO classification 2017
The current WHO classification of salivary gland tumours has 5 categories
- malignant tumours
- benign tumours
- non-neoplastic epithelial lesions
- benign soft tissue lesions
- haematolymphoid tumours
What is the most common of the 22 primary epithelial salivary gland malignant tumours in the WHO classification?
mucoepidermoid carcinoma
what is pleomorphic adenoma?
benign salivary gland tumors, which predominantly affect the superficial lobe of the parotid gland
