Salivary Glands Flashcards
Functions of saliva?
Protection: - lubrication, barrier and clear sugar Buffering: - protect demineralisation Pellicle: - Ca binding Maintenance of tooth integrity: - Ca and Pi supersaturation Antimicrobial: - prots and peps with antibacterial Tissue repair: - GFs Digestion: - breakdown food with enzymew Taste: - bind to taste substances
Salivary glands - Types of saliva?
Serous:
- watery, from parotid and submandibular
Mucous:
- slimy, from sublingual and minor glands
Salivary glands - Name the major glands - cell type? Position? Duct? Innveration (para and symph)?
Parotid:
- pure serous, in front of the external ear, from the Stensen’s duct and innervated by IX
Submandibulae:
- mixed cell type mainly serous, posterior pairt of the floor of the mouth, from the Wharton’s duct and innervated by VII
Sublingual:
- mixed but mainly mucous, anterior part of the floor of the mouth, from the Ducts of Rivinus, innervated by VII
Symph: all via the superior cervical ganglion
Salivary glands - minor salivary glands - #? Secretion type? Location? Names?
#: - 600-1000 Secretion type: - mucous Location: - virtually everywhere except gingival and alveolar mucosae Names: - labial, buccal, palatal and lingual
Salivary glands - general structure - fruit comparisons and what it relates too?
Similar to a bunch of grapes
- grapes; secretary end pieces (acini)
- stems; ducts
- air; CT
Salivary glands - type of ducts - names? CT location?
Intercalated duct
Striated duct
Secretary duct
CT is located surround the ducts
Salivary glands - structural units of a salivary gland - epith? (Main part? Ducts? Special cells?) And CT? (Main part? Speta role? Location? Carries?)
Epith: - secretary end-pieces - ducts (intercalated, striated and secretory) - myoepith; on acini and ducts CT: - capsule - speta; divide gland into lobes and lobules - surrounded all epith units - carries; blood and nerve supply
Salivary glands - lobes and lobules- created by? Differences?
Lobes:
- largest unit and separated by thick speta
Lobules:
- smaller
- separated by thin speta
- contains intercalated and striated ducts (intralobular ducts)
Salivary glands - functional arrangement of a salivary gland - anatomy? Intra to interlobular
Intralobular:
- serous acinus, mucous acinus (myoepith cell) and serous demilune, intercalated duct leading to the striated duct
Interlobular:
- collecting duct
Salivary glands - development of salivary glands - starts? Gland derivatives? CT derivatives?
Starts during the 6th week (parotid) Parotid and most minor gland: - from the ectoderm Submandibular: ectoderm Sublingual: endoderm All lingual minor glands: endoderm CT: - probably ectomesenchyme
Salivary glands - development of salivary glands - 8 weeks - Initiation? Activates? Formation? Final stage? Cellular differentiation depends on? Age changes?
Initiation:
- start via epith-mesenchymal interactions
Activation:
- this allows epith prolif, until forms a lobule shape
Formation:
- lobule formation
Final stage:
- epith canalisation (form the ducts via epith) and cellular differentiation
Continous process until 2 years old
Cellular diff:
- epith-mesenchymal inter
- nerves: symph and para (influence overall growth of gland)
- form secretory cells (epith cells) and myoepith
Age changes:
- increased fat cells
Salivary gland - resting secretion - when it occurs? Role?
It occurs:
- throughout day and night
Role: mouth and oro-pharynx
- most, lubricated and protected
Salivary gland - volume of saliva? Flow rate equation? Rate (unstim vs stim)?
Volume: - 500-750 ml/day (90% major) Great variability between individual Flow rate: - volume (ml) ÷ time (mins) Unstim: 0.3ml/min (mainly submandibular) Stim: 1.75ml/ml (mainly parotid and submand)
Salivary gland - anatomy?
Anatomy:
- acinus, capsule, septum, lobe, secretory units, and ducts (intercalalted, striated and collecting)
Salivary gland - acinar cells - what are they? Role? Specialised shape? Cell types?
What are they: - cells comprising of acinus (secretory end piece) Role: - saliva production (serous or mucous) Specialised shape: - pyramidal shaped cells for function Cell types: - serous acinus, mucous acinus and serous demilune
Salivary gland - serous acinus cells - nuc location? RER? Cytoplasmic apperance? Discharge secretions where?
Nuc loc: - basal part of cell RER: - basophilic Cytoplasmic apperance: - granular Discharge secretion: - into tubular lumen via intracellular canaluculi running between the cells
Salivary gland - mucous acinar cells - cytoplasm (stain)? Nuc? Granules?
Cytoplasm: - pale, mucin lost or not easily stained, cytoplasm can appear empty in a H&E stain Nuc: - flattened nuc Granules: - large mucin granules
Salivary gland - serous demilunes - what is it? Location? Discharge?
What is it: - crescent of serous cells Location: - mucous acinus capped by serous cells Discharge: - via the intercellular canaliculi between the mucous cells
Salivary gland - myoepithelial cells - located? Shape? Grouping? Process #? Function?
Located: - on acini and intercalated ducts Shape: - star shaped Grouping: - 1,2 or 3 cells in each salivary body Process #: - 4-8 processes Function: - contractile elements - squeeze acinus (aid secretion) - regulate duct lumen size
Salivary gland - intercalated ducts - type of cell? Nuc?
Type of cell:
- low cuboidal cells
Nuc:
- large central nuc
Salivary gland - striated ducts - not present? Cell shape? Mod? Folding?
Not present: - sublingual glands Cell shape: - columnar shaped cells Modificiation: - of primary saliva Folding: - massive basal membrane folding
Salivary gland - collecting ducts - lumen? Cell type? Merges?
Lumen: - large lumen Cell type: - pseudostratified columnar epith Merges: - stratified near termination merges with stratified squamous oral epith
Salivary gland - histology - parotid composition? Submandibular composition? Sublingual composition?
Parotid composition:
- composed of serous acinu
- large number of ducts
- adipocytes and plasma cells
Submandibular gland:
- mixed but more serous cells, also myoepith and demilunes
- intercalated and striated ducts are less than in parotid
Sublingual:
- mixed, but mostly mucous cells
- intercalated ducts are short and difficult to recognize
- intralobular ducts fewer on # than parotid and submand
Summary of major salivary glands - names? Sizes? Location? Excretory ducts? Striated ducts? Intercalated ducts? Acini? Fluid characterisitics? Innervation?
Parotid:
- largest, encapsulated
- behind the mandibular ramus, ant and inferior to ear
- Stenson’s duct: open opposite max second molar on buccal mucosa
- short straited ducts
- long intercalated ducts
- serous acibu
- secreting watery, but amylase-rich
- innveration XI
Submandibular
- intermediate, encapsulated
- beneath the mandible
- Wharton’s open near lingual frenum on the floor of the mouth
- striated duct long
- intercalated short
- mainly serous
- vicous, mucin rich
- VII
Sublingual
- smallest, no capsule
- floor of mouth
- Bartholin’s: opens at same area as the submand, with additional ducts (Rivinus) at submand folds
- straited and intercalated absent
- mucous
- vicious and mucin rich
- VII
Summary of minor salivary gland - names? ducts? Acini? Fluid? Innveration?
All - rare striated and intercalated ducts Palatinal - mucous - mucin rich - VII Buccal - mucous - mucin rich - VII Labial - mucous - mucin rich - VII Von Ebners (lingual) - serous - watery and lipid rich - IX Retromolar - mucous - mucin rich - VII/IX
General structure of salivary glands?
Like a bunch if grapes:
- grapes are the acini
- stems are the ducts
- air is the CT
Functional arrangement of salivary glands - chronology?
Inner to outer:
- secretary duct
- striated duct
- interclalated duct
- acinus
Salivary glands - serous acinar cells - organelles?
Organelles:
- Nuc at basal cell
- basophillic RER
- granular apperance
- cells discharge their secretions into the tubular lumen via intracellular canaliculi running between cells
Salivary glands - mucous acinar cells - organelles?
Organelles:
- plate cytoplasm- mucin lost ir not easily stained, so cytoplasm can appear medium in H&E Staines secretion
- flattened basal nuc
- large mucin granules
Salivary glands - saliva - characterisitics? Resting state and stimulated state? Flow rate?
Compostion:
- hypotonic fluid (99% water and 1% dry matter)
- .5 -1.5 litres daily
- resting state 2/3 volume prod by submand
- stimated state 60% by parotid
Salivary glands - saliva - composition? Variations?
Varies:
- from gland to gland, rats of secretion and between species
Compostion:
- 99% water
- electrolytes and inorganic constituents
- formed elements and organic constituents
Salivary glands - saliva - electrolytes?
Cations:
- Na, K, Ca and Mg
Anions:
- Cl, HCO3, Pi, thiocynate, SO4, F, I, and OH
Salivary glands - salivary secretion - stage I and stage II?
Stage I:
- electrolyte transport bu acinar cell go produce isotonic saliva
Stage II:
- ductal modification of electrolyte composition of primary saliva to produce hypotonic saliva ⁰
Salivary glands - salivary gland secretion - Stage I?
Step I:
- ACh bind muscarinic receptor on acinar cell
- increased Ca influx
- from increased Ca its caused Ca gated channels to remove K and take in Cl and HCO3
Step 2:
- Na in via paracellular to balance charge
- H20 follows Na (paracell or transcell)
- aquaporins allow h20
- high perm to h20
- causes cell shrinkage
Step 3:
- act of Na/K/Cl cotransporter to take in Na
- Na/H exchange to take in Na
- Na/K pump to take in K and remove Na (with ATP)
Step 4:
- stimulus removed; the free intracellular Ca, cell volume, cytoplasmic pH and transport return back to normal
Salivary glands - salivary secretion - stage II
From striated ducts Step 1: - Na/K pump removes Na into plasma Step 2: - reansorption of Na and Cl via Na and Cl channels, Na/H exchanger and Cl/HCO3 transporter
All duct is impermeable so water and stays in lumen
Result in saliva with increased HCO3, reduced Cl and Na
Salivary glands - inorganic saliva composition and flow rate relation?
Compostion:
- salivary secretion as a function of salivary flow rate compared with concentrated ions in plasma
- saliva is hypotonic to plasma at all flow rates
- salivary conc of HCO3, Cl and and Na increases with increasing flow rate
- salivary conc of K decreases with increases flow rate
Salivary glands - formation of organic constituents of saliva? Secretory pathways? Prot conc dependent on?
Mostly by acinar cells (but can be ductal too)
- proteins are the major organic component
component:
- prot conc depend in duration of stim and flow rate
(Long stim and high flow rate results in high saliva total prot conc)
Secretory pathways:
- constitutive exocytosis (continous) minor
- regulated exocytosis (major)
What is exocytosis?
- A process which a cell transports secretory products through the cytoplasm to the plasma membrane
- Secreotry products are packed into teanposrt vesicles
What is constitute exocytosis? Prot conc? Flow?
- prots not concentrated into secretory vesicles awaiting stimulus
- continous flow of protein in small vesicles to plasma mem
- responsible for a continous secretion if several proteins without stim
What is regulated exocytosis? Controlled by? Storage? Secretion?
- acceleration of constitutive
- controlled by symph innveration
- after synthesis proteins stored in granules
- stim, granules empty content into lumen
Salivary gland - buffering action of saliva - defintion? Key components? Other buffers?
Buffering capacity: ability of the saliva to maintain the pH when exposed to acids
HCO3:
- from major glands
- conc increases with flow rate
- miminises drop in pH around teeth after consumption of sugar (min demineral)
Buffers:
- phosphate and protein
Salivary gland - What is a Stephan curve? Fluor vs hydroxy?
The change in plaque pH influencing demineralisation and remineralisation
Fluroapatite - 4.5 demin
Hydroxyapatite- 5.5 demin
Saliva - remineralisation of teeth - composition?
Composition:
- supersaturaed with Ca and PO4
- high flow rate associated with Caz PO4, OH and pH (reduced demin, increases remin and calculus form)
- helped by presence of flouride in saliva
Saliva - organic component - constituents?
Constituents:
- prots, carbs, lipids and small organic molecules
Proteins:
- amylase, lipase, mucin, statherin, IgA,
Saliva - organic components - amylase (secreted by? Role? Function? Inactivated? Plaque?)
Secreted by: - parotid glands Role: - carbohydrate digestion Function: - breakdown starch and maltose Inactivated: - low pH Plaque: - breakdown of plaque
Saliva - organic components - lipase? (Secreted by? Role?)
Secreted by: - lingual minor glands (Von Ebner) Role: - fat digestion - active at gastric pH - digestion of milk fat for newborns
Saliva - organic components - mucin? (Molecule type? Formation of mucus? Role? Location? Function? Important role? Immune?
Molecule type:
- complex molecule (peptide core and oligosaccardie chains)
Mucus:
- mucin + water
Role to lubricate
Location:
- on all oral soft tissues (prevents drying and provide barrier)
- hydrophilic and likes water and so stops dehydration
Important for pellicle
Aggregate bacteria
Saliva - organic components - statherin (prevent? Pellicle?)
Prevent:
- precipitation of Ca and PO4 (supersaturated), good for mineral
- but can inhibit remineral, but cant permeate early carious lesions (not a major problem)
Prevent calculus
Present in enamel
Saliva - organic components - antimicrobial components of H20, amylase, lysozyme, peroxidase, lactoferrin, histatins and cystatins?
Water - cleansing
Amylase - bacterial adhesion
Lysozyme - leaves polysacc wall
Peroxidase - same as above
Lactoferrin - bind Fe inhibit bacteria growth and adherence
Histatins- inhibit growth Candida
Cystatins - inhibit tissue damaging bacterial enzymes
Saliva - organic components - IgA (secretion? Synth? Specificity?
Secreted by - minor glands Synth: - plasma cells in CT Specific: - stim by bacteria against specific antigens provides local immunity
Salivary glands - saliva secretion - neural control (parasympth and sympth)
Parasymth:
- from brainstem and salivary nuclei (sup pons and inf brainstem nuc)
- VII nerve to the sub glands
- XI nerve to the parotid via otic ganglion
- to the submandibular ganglion
- ACh release to muscarinic receptors in the salivary glands
Sympth:
- thoracic spinal cord (T1-4)
- to the superior cervical ganglion
- via the sympth nerve
- to the salivary gland releasing NA act b-adr
Salivary glands - saliva secretion - neural control - reflex defintion? Stimuli? Reaction?
Reflex:
- innate, automatic, predicate, repsonse involving the CNS, to a known stimulus
Stimuli:
- associated with feeding
Reaction:
- complex secretomotor and vasometer innveration
Lack uniformity of response between gland and species
Secretion dependant in reflex activity
Salivary glands - saliva reflex - gustatory (reflex type? Stimuli? Flow? Innervation?
Reflex type: - unconditioned Stimuli: - via taste buds - basic tastes cause secretion Sour > Salt > Bitter > Sweet Flow: - max flow achieved using 5% citric acid (7ml per min) Innervation: - VII, IX and C nerves
Salivary glands - saliva secretion - neural control - flow chart?
Sensory info from mechanoreceptors and chemo receptors Cerebral cortex Salivary centre in medulla Autonomic Salivary glands Secretion
Salivary glands - masticatory salivary reflex (stimulus from? Innervation? Reflex pathway?)
Stimulus from:
- mechanorecprtors afferent neurons affecting periodontal ligament, oral mucosa, TMJ and muscles
Imnervation:
- V
Reflex pathway:
- unilateral
- stim of one side of the mouth induces ipsilateral salivation
What is Lashley cup?
A measure of flow rate
To be placed near the duct opening to collect saliva
Outer chamber for suction to buccal mucosa
Salivary glands - olfactory salivary reflex (type of repsonse? Gland?)
A unilateral response of the parotid gland
No repsonse of the parotid to the odour of lemon
But taste has a reaction
But with the submand gland, the odour of beef increases flow rate of saliva
Olfactory parotid reflex doesn’t exist
Olfactory submand reflex does exist
Salivary glands - saliva secretion - neural control (sympth nerves? Parotid gland - innervation and synapse? Submand and subling - innveration and synapse?)
Sympth nerves:
- from the synoatheric trunk follow blood vessels
Parotid gland:
- receives parasynth signals from IX synoases in otic ganglion
Submand and sublingual:
- parasympth signals form facial nerve synapses in the mand ganglion
Unconditioned salivary reflex?
Gustatory and masticatory and olfactory
Higher centres: - facilitate, also inhibit (dry mouth with anxiety) but can enhance response
Condition salivary reflexes?
Pavlov’s dogs
Not easily demonstrated in man
Assocaitaion of sound with food without food stimulus
Salivary glands - saliva secretion - neural control - psychic stimuli hypothesis?
Mouthwatering occurs on anticipation if sight of food when hungry, but it is more of a sudden awareness of saliva in mouth rather than more
Salivary glands - saliva secretion - neural control (signal factord)
Sensory recpeotes for a salivary reflex or a condition reflex
But cant enhance
Factors affecting salivary flow rate?
Increased presence of food in mouth - chemical and mechanical Increased of smell of food Time of day - increased in afternoon and reduced in night Season - lowest in winter and highest in summer Light: - bright increased and dark decreased Hydration: - reduced dehydrated Body positon: - increased standing and reduced sitting Drugs: - on glands and nerves Reduces with age
Xerostomia - defintion? Causes?
Defintion:
- unstimulated flow less than 50% of normal
Causes:
- disease such as systemic, intrinsic or extrinsic
- medication such as analgesics antidepressants and anti-histamines
- dehydration, nerve damage tobacco and alcohol and stress and anxiety
Xerostomia affect on QoL?
Eating: - taste alteration - dysphagia - mastication problems - avoid foods Social - speech difficulties - bad breath - sip water QoL: - embarrassment and self conscious - irrtibale - discomfort with dentures
Physical impact of Xerostomia - oral cavity? Mucosa? Tongue teeth? Lips? Saliva?
Oral cavity:
- food debris, poorly fitting denture and bad breath
Mucosa:
- burn sense, dry and sticky mucosa, dental mirror sticks
- mucositis, ginguvigs, mouth lesions and infection
- infection, ulcers and fissures, and erythematosus
Tongue:
- erythrma, atrophy of filiform, dry and fissured
Teeth:
- dental caries (cervical and root caries) and demin
Lips:
- cracked lips, peeling and fissuring and angular cheiltis
Saliva:
- reduced pooling, stringy and frothy saliva
Sjögrens’s syndrome - what is it? Prevalence? Ages? Symptoms? Causes? Diganoses? Treatment?
Long term autoimmune disease affecting body moisture producing glands (mouth and dry eyes)
Prevalence:
- 1/100
Lab test and imaging
Between 35-50
More common in females
Family history
Symptoms:
- dry eyes and dry mouth
- dry throat, dry nose, cracked tongue dry skin, persistent dry cough and prolonged fatigue
Causes:
- unknown but combination of genetics hormonal and environmental
Diagnoses:
- blood test via antibodies and rheumatoid factor
Salivary flow test
Eye test - function of lacrimal glands
Lip/salivary gland biopsy - reveal lympho closed around salivary due to gland inflammation
No known treatment
