Saliva Flashcards
Name the 3 major salivary glands and state their type of secretion
- Parotid - 99% serous
- Submandibular - mixed mucous/serous
- Sublingual - mainly mucous
What is the function of the resting saliva secretion?
It helps to keep the mouth and oropharynx moist, lubricated and protected
State the values of the unstimulated flow rate and the stimulated flow rate
unstimulated: 0.3ml/min
stimulated: 1.75ml/min
Composition of saliva at rest from parotid, submandibular, sublingual and minor glands
P: 10%, SM: 70%, SL: 10%, MG: 10%
Composition of saliva when stimulated from parotid, submandibular, sublingual and minor glands
P: 60%, SM: 30%, SL: 5%, MG: 5%
Name 7 factors influencing the stimulated flow rate
- Mechanical stimuli (unilateral > contralateral)
- Gustatory and olfactory stimuli
- Gland size
- Age
- Food intake (nature of food - acidic)
- Vomiting
- Visual stimulus
Name 9 functions of saliva
- Protects tissues
- Enhances taste
- Lubricates food
- Speeds oral clearance of food
- Facilitates removal of carbohydrates
- Inhibits demineralisation / Encourages remineralisation
- Discourages bacteria growth
- Neutralists organic acids
- Recycles ingested fluoride to the mouth
What is xerostomia? When is somebody perceived to suffer from it?
Xerostomia refers to the lack of saliva.
It is perceived when the unstimulated saliva flow is less than 50% of normal.
What problems can xerostomia pose to a person? (X5)
- increased risk of caries
- mucosal infections eg fungal
- pain from oral mucosa
- difficulty chewing/swallowing/speaking
- impaired taste
What is the main constituent of saliva?
Water (99%)
What are the major inorganic constituents of saliva? (X7)
Sodium Potassium Chloride HCO3- Calcium Magnesium HPO4-
Name 3 minor inorganic ions in saliva
I-
SCN-
F-
Factors affecting saliva flow rate (x8)
- Increased presence of food in mouth - chemical and mechanical
- Thought/smell of food
- Time of the day (increased in the afternoon, decreased at night)
- Season (winter>spring>autumn>summer)
- State of hydration (decreases when dehydrated)
- Body position
- Drugs
- Age
Describe the structure of a salivary gland
Ducts lead from the acini starting with the intercalated ducts to striated ducts to secretory ducts
Name the active components of the salivary gland
Acinus and striated duct
Difference between minor and major glands
Minor glands are smaller and have shorter ducts
Function of connective tissue inn salivary gland
The capsule and septa -
Surrounds all epithelial units and carries blood and nerve supply
Are the minor salivary glands mainly mucous or serous?
Mucous
Where are the minor salivary glands found?
Found almost everywhere in the oral mucosa, except the gingival and alveolar mucosa
Name 4 minor salivary glands
- lingual glands
- buccal glands
- palatal glands
- labial glands
Function of posterior mucous glands
Lubricates pharynx and soft palate
Function of anterior mucous glands
Lubricates the tip of the tongue, provides protection of the tongue from abrasion of teeth
Name an example of a lingual gland
Serous gland of von ebner
Where can serous glands of von ebner be found? What is the function?
Found in taste buds in the tongue
Fxn: allow taste sensation by dissolving chemicals, enzyme lipase is present here to help clear the tongue of fatty deposits, thus allowing proper functioning of the taste buds
Name the two cranial nerves carrying parasympathetic supply to the salivary glands
CN VII , IX
Which nucleus does the facial nerve innervate?
Superior salivatory nucleus
Which nucleus is innervated by the glossopharyngeal nerve?
Inferior salivatory nucleus
From where does the spheno palatine ganglion receive its input?
What does the spheno palatine ganglion supply?
Receives input from the superior salivatory nucleus via the greater petrosal nerve
Supplies the palatal glands
From where does the submandibular ganglion receive its inputs from?
What does it proceed to supply?
Submandibular ganglion via chorda tympani from superior salivatory nucleus
Supplies the submandibular, sublingual, lingual and labial glands
What is the otic ganglion innervated by?
What does it supply?
CN IX-Inferior salivatory nucleus via lesser petrosal nerve
Parotid gland
Where do salivary glands get its sympathetic supply from?
Upper thoracic spinal nerves
lateral horn -> superior cervical ganglion
When does the development of salivary glands start?
Around 6 weeks I.u.l
Parotid gland begins to develop followed by the other glands
What components are derived from the ectoderm?
Epithelial components for the parotid and most minor glands
From where are epithelial components for the submandibular and sublingual glands derived from?
Ectoderm and endoderm
From where are epithelial components of lingual minor salivary glands derived?
Endoderm
From where are connective tissue in all salivary glands derived?
Ectomesenchyme
Which components are derived from the endoderm?
Epithelial components of lingual minor salivary glands
Which epithelial components are derived from both the ectoderm and endoderm?
Epithelial components for the submandibular and sublingual glands
What is derived from ectomesenchyme?
Connective tissue of all salivary glands
What is the sympathetic nervous system required for
?
Cellular differentiation
What is cellular differentiation in salivary glands dependent on? (X2)
- epithelial - mesenchymal interactions
- sympathetic nervous system
What does the parasympathetic nervous system influence?
Overall growth of gland
Which salivary glands are found underneath the mandibular process? (X2)
Submandibular and sublingual glands
Which salivary gland can be found above the mandibular process?
Parotid gland
Shape of acinus
Pyramidal shaped and polarised
Name the three classifications of acinus
- serous
- mucous
- mucous + serous demilune
Where can myo-epithelial cells be found?
Acini and intercalated ducts
Function of myoepithelial cells (x2)
- contractile elements to “squeeze” acinus, assisting secretions into lumen
- regulates duct lumen diameter
Histological presentation of intercalated ducts
Low cuboidal cells
Large central nucleus
Which glands do not contain striated ducts?
Sublingual glands
Histological presentation of striated ducts
Columnar shaped cells with massive basal membrane folding, which appears as striations
Histological presentation of secretory ducts
Large lumen, with pseudostratified columnar epithelium which is stratified near termination
What is the effect of a high flow rate on the composition of parotid saliva?
Higher sodium concentration in saliva
What is the effect of a low flow rate on the composition of parotid saliva?
Lower sodium concentration in saliva
What are the organic constituents of saliva secreted by?
Acinar cells
List the processes involved in the secretion of organic components of saliva (x4)
- formation of peptides
- post translational glycosylation of peptides
- processing and packaging of organic components
- formation of condensing vacuoles
What is the main mechanism for secretion of components into saliva?
Exocrine - mainly merocrine
Neural control of salivary secretion:
What does the parasympathetic and sympathetic nerves secrete?
Parasympathetic nerves secrete acetylcholine
Sympathetic nerves secrete noradrenaline
Name 3 possible neuropeptide transmitters involved in the control of saliva secretion
Substance P
Vasoactive intestinal peptide
CGRP
Which stimuli results in the most effective gustatory salivary reflex?
Sour > salt > bitter and sweet
Is the olfactory-parotid reflex present in humans
No
Is the parotid-submandibular reflex present in humans?
Yes
What gives rise to the parotid-submandibular response?
Chewing gives the parotid response
Smell gives the submandibular response
What is the role of the higher centres in relation to saliva secretion?
Association of the stimulus with actual food intake rather than the direct oral stimulus of food intake
Higher Centres can facilitate or inhibit saliva secretion, but cannot enhance it
Name 6 major constituents of saliva and GCF
- IgA
- sodium
- potassium
- protein
- bicarbonate
- phosphate
Compare the IgA and protein levels between saliva and GCF
10x higher in GCF than in saliva
Which constituent is roughly about the same in saliva and GCF ?
Potassium
Which constituent is vastly higher in GCF than saliva and which is much lower?
Sodium much higher in GCF
Phosphate much lower in GCF
Name the major constituents of saliva that are anti bacterial x5
Amylase Cystatin Histatins Mucins Peroxidase
Name an anti-fungal constituent of saliva
Histatin
Name 2 anti-viral constituents of saliva
Cystatin, Mucins
Name 2 constituents of saliva with buffering capacity
Carbonic anhydrases, Histatins
Name 3 constituents of saliva involved in digestion
Amylases, Mucins, Lipases
Name 2 constituents of saliva involved in lubrication
Mucins, Statherins
What is the acquired pellicle?
A cell-free proteinaceous layer of macromolecules on the mineral surface of teeth, containing peptides, proteins, enzymes, glycoproteins, lipids and glycolipids
How does carbonic anhydrase IV offer protection to tooth?
It binds to the pellicle and offers localised protection through the removal of H+
What is Statherin?
An amphipathic molecule/phosphoprotein
Function of Statherin
Aids A. Viscosus and F. nucleatum binding to HAp
Which is the most abundant salivary enzyme?
a-amylase
Action of a-amylase in saliva
Hydrolyzes a(1,4) glycosidic bonds of polysaccharides
Where is lingual lipase secreted from?
Von Ebner’s glands of the tongue
Action of lingual lipase
Hydrolyzes medium to long-chain triglycerides into diglycerides and free fatty acids
2 main functions of mucins
- Tissue coating
2. Lubrication
What effect does lactoferrin have?
Bacteriostatic function, blocks the growth of iron dependent organisms
