Salivary glands Flashcards

1
Q

What happens to saliva composition with age?

A

Saliva composition changes with age.

Time is a major factor in determining the content and composition of saliva.

This is relevant for understanding the impact of changes in saliva composition with age on oral health. Such as swallowing of food and protection against dental caries.

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2
Q

What are the types of salivary glands based on function?

A

Serous producing glands

Mucous producing glands

Mixed glands

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3
Q

What are the types of salivary glands anatomically?

A

3 pairs of major glands:

Parotid, submandibular, sublingual

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4
Q

How common are salivary gland tumours?

A

Rare but serious

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5
Q

What type of ducts do the major salivary glands have and what kind of saliva do they produce?

A

Parotid: Watery - serous saliva rich in amylase, proline rich proteins (Stenson’s duct)

Submandibular gland - More mucinous (Wharton’s duct)

Sublingual gland - Viscous saliva (Ducts of rivinus or duct of bartholin)

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6
Q

What kind of epithelium does the floor have?

A

Non-keratinized stratified squamous epithelium.

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7
Q

What salivary glands should be examined during examination of the oral cavity?

A

It is important to palpate the major salivary glands during extraoral examination

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8
Q

What are the types of minor salivary glands? Where are they located?

A

Minor salivary glands are not found within gingiva and anterior part of the hard palate.

Serous minor glands are von ebner glands below the sulci of the circumvallate and folliate papillae of the tongue.

Glands of Blandin-Nuhn located on the ventral surface of the tongue.

Palatine, glossopalatine glands are pure mucous.

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9
Q

Where are serous minor glands located?

A

Von ebner glands below the sulci of the circumvallate and folliate papillae of the tongue.

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10
Q

Where are glands of Blandin-Nuhn located?

A

Located on the ventral surface of the tongue.

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11
Q

What cancer is commonly seen in glands of Blandin-Nuhn?

A

Ventral surface of the tongue

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12
Q

What glands produce the saliva and how much do they contribute?

A

Most from submandibular (65%)

Smaller proportion from parotid gland (25%)

Lingual gland (5%)

Minor salivary glands produce the remaining (5%)

Total saliva produced per day is approximately 700 - 1200 ml per day

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13
Q

What is the protective function of saliva?

A

Lubricant (glycoproteins)

Barrier against noxious stimuli

Washing non-adherent and acellular debris

Formation of salivary pellicle (Calcium binding proteins: Tooth protection and plaque)

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14
Q

How does saiiva produce buffering action? Why is this useful?

A

Phosphate ions and bicarbonate.

Bacteria require specific pH conditions

Plaque microorganisms produce acids from sugars

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15
Q

What are the anti-microbial actions of saliva?

A

Lysozyme hydrolyzes cell walls of some bacteria

Lactoferrin binds free iron and deprives bacteria of this essential element

IgA agglutinates microorganisms

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16
Q

How does saliva maintain tooth integrity?

A

Calcium, fluoride and phosphate ions are exchanged with tooth surface

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17
Q

What are the tissue repair functions of saliva?

A

Bleeding time of oral tissues shorter than other tissues

Resulting clot less solid than normal

Remineralization

Several growth factors have been identified in saliva and contribute to healing process

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18
Q

How does saliva help with taste?

A

Solubilizing food substances that can be sensed by receptors

Solubilized food has a trophic effect on receptors

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19
Q

How is saliva flow regulated throughout the day?

A

0.5L/24h secreted mostly at day time

Saliva flow is simulated through neural pathway triggered by foods’ chewing and tasting

Almost no salivary secretion during sleep

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20
Q

What rate of saliva production is considered normal and what is low?

A

Very low UWSFR<0.1ml/min
Low 0.11 - 0.25ml/min
Normal UWSFR >0.25ml/min

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21
Q

How is UWSFR different between males and females?

A

Men produce more saliva than females

UWSFR is significantly affected by CPI, OHI-S, and BMI

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22
Q

How are UWSFR and risk factors correlated?

A

High BMI scores, moderate-to severe gingivitis and low level of oral hygiene

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23
Q

Where does the parotid arise embryologically? When is it first formed?

A

Parotid is ectoderm in origin (Forms 4-6 weeks of embryonic

life)

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24
Q

Where and when do the sublingual and submandibular salivary glands originate?

A

Sublingual-submandibular are endoderm in origin

Sublingual and minor glands develop around the 8 - 12 week mark

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25
Q

What do salivary glands arise from? How do they form?

A

Differentiation of ectomesenchyme

Development of fibrous capsule

Formation of septa that divide the gland into lobes and lobules

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26
Q

What are the types of tissue in salivary glands?

A

Glandular secretory tissue (Parenchyme)

Supportive connective tissue (stroma)

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27
Q

What are the types of ducts in salivary glands?

A

Intercalated ducts -> striated ducts -> Major collecting duct

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28
Q

What are the main features of serous glands?

A

Cytoplasm is dark and has a rough appearance with no lumen

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29
Q

What do mucinous cells look like

A

Cytoplasm looks clear

Nucleus small

Cells are in a circle bound by tight junctions with a lumen in the middle

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30
Q

What is the difference between primary and secondary saliva?

A

Primary saliva:

Serous and mucous cells.

Intercalated ducts

Modified saliva:

Striated and terminal ducts

End product is hypotonic

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31
Q

What controls fluid and electrolyte production in saliva?

A

Parasympathetic innervation

Binding of ACh to muscarinic receptors triggers opening of channels of K+, Cl-, Na+, and

Norepinephrin via alpha-adrenergic receptors triggered by substance P which activates the Ca2+

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32
Q

How are myoepithelial cells arranged on salivary glands?

A

1, 2, or 3 myoepithelial cells in each salivary and piece body.

4 to 8 processes

Desmosomes between myoepithelial cells and secretory cells

Myofilaments frequently aggregated to form dark bodies along the whole process

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33
Q

What is the potential issue with myoepithelial cells.

A

Myoepithelial cells are responsible for many cancers such as pleomorphic adenomas

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34
Q

What are myoepithelial cells made up of?

A

Intercalated ducts are more spindled-shaped and fewer processes

Ultrastructurally very similar to that of smooth muscle cells

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35
Q

What is the function of myoepithelial cells?

A

Support secretory cells

Contract and widen the diameter of secretory acini

Contraction may aid in the rupture of acinar cells of
epithelial origin

36
Q

How does duct diameter get affected by the location?

A

As we go from the terminal ends to the major duct the duct increases in size

37
Q

What do intercalated ducts look like?

A

They have a small diameter

They are lined by small cuboidal cells

Nucleus located in the center

Well-developed RER, Golgi apparatus, occasionally secretory granules, few microvilli

Myoepithelial cells are also present

Intercalated ducts are prominent in salivary glands having a watery secretion (such as parotid gland)

38
Q

What do striated duct cells look like?

A

They are columnar cells

Contain a centrally located nucleus

Eosinophilic cytoplasm

Prominently striations which are indentations of the cytoplasmic membrane with many mitochondria present between the folds.

Some RER and some Golgi, short microvilli

They are basal cells

39
Q

What are the structural properties of terminal excretory ducts?

A

Near the striated ducts they have the same
histology as the striated ducts

As the duct reaches the oral mucosa the
lining becomes stratified

Goblet cells, basal cells, clear cells.

Alter the electrolyte concentration and add
mucoid substance.

40
Q

What happens to ducts as we go from terminal ends to the major duct?

A

Cells surrounding the lumen become more columnar

They become larger

41
Q

What do the terminal excretory ducts look like?

A

Near the striated ducts they have the same histology as striated ducts

As the duct reaches the oral mucosa the lining becomes stratified

Goblet cells, basal cells clear cells

Alter the electrolyte concentration and add mucoid substance

42
Q

oajsido

A

Autonomic Nervous System

Striated and terminal ducts

modification via reabsorptiona nd secretion of electrolytes

Final product is hypotonic

Rate of salivary flow

43
Q

What are the features and types of inflammatory cells in salivary glands?

A

Fibroblasts

Inflammatory cells

Mast cells

Adipose cells

ECM

Collagen and oxytalan fibers

44
Q

How is salivation controlled?

A

No direct inhibitory innervation

ParaSNS and SNS impulses control salivation but ParaSNS is more prevalent.

ParaSNS impulses may occur in isolation, evoke most of the fluid to be excreted, cause exocytosis, induce contraction of myoepithelial cells (sympathetic too) and cause vasodilatation.

45
Q

What are the types of innervation that salivary glands receive?

A

2 types of innervation:

Epilemmal and hypolemmal

Beta-adrenergic receptors that induce protein secretion

L-adrenergic and cholinergic receptors that induce water and electrolyte secretion

46
Q

How do hormones affect salivary gland production?

A

Hormones can influence the function of salivary glands. They modify salivary content but not flow.

47
Q

What are the age related changes in salivary glands?

A

Fibrosis and fatty degenerative changes

Presence of oncocytes (eosinophilic cells containing many mitochondria)

48
Q

How does heavy alcohol intake affect the parotid gland?

A

Alcohol causes an increase in size and fatty acid content of parotid gland

49
Q

What kind of gland is the submandibular gland?

A

Mainly serous with some areas of mucous

50
Q

What kind of gland is the sublingual gland?

A

Mucous mainly with serous demilunes

51
Q

What are the clinical considerations of the anatomy of ducts of salivary glands?

A

Obstruction

Role of drugs

Systemic disorders (eg sjogren’s syndrome)

Bacterial or viral infections

Therapeutic radiation

Formation of plaque and calculus

52
Q

What happens if we have obstruction and backing up of saliva?

A

Loss of acini replaced by fibrous connective tissue

53
Q

What is sjogren’s syndrome?

A

Sjogren’s syndrome is an autoimmune disease which is characterized by autoimmune destruction of secretory acini which end up being replaced by fibrous tissue.

54
Q

How does a mucocele/mucous retention cyst form?

A

Mucocele forms from trauma which can destroy the duct and so saliva can start being secreted beneath the oral mucosa

55
Q

How can sialoliths be diagnosed?

A

Can be seen on radiograph

56
Q

How can a bacterial infection affected secretions?

A

Pus can come out from the gland to the oral cavity

57
Q

What commonly causes xerostomia?

A

Drugs

Radiotherapy to head and neck

Sjogren’s syndrome

Psychogenic?

HCV, and HIV disease?

58
Q

What are some uncommon causes of xerostomia?

A

Chronic graft versus host disease

Sarcoidosis

Cystic fibrosis

Diabetes mellitus

Amyloidosis

Haemochromatosis

Wegener’s disease

Salivary gland agenesis

Triple A syndrome

Cholinergic dysautonomia

Others

59
Q

What drugs lead to xerostomia?

A
Drugs with anti-cholinergic action:
Atropine and analogues
Tricyclic antidepressants
Serotonin re-uptake inhibitors
Anti-histamines
Anti-emetics
Anti-psychotics
Drugs with sympathomimetic action:
Decongestants
Bronchodilators
Appetite suppressants
Amphetamines
Other drugs:
Lithium
Omeprazole and others
Oxbutynin
Disopyramide
Dideoxyinosine
Didanosine
Diuretics
Protease inhibitors
60
Q

What kind of caries does xerostomia lead to?

A

Cervical caries is common

Rampant caries in children

61
Q

What kind of gingival disease does xerostomia lead to?

A

Acute gingivitis

Chronic gingivitis

62
Q

What can lead to salivary gland enlargement associated xerostomia?

A

Sjogren’s-related inflammation

Sialadenitis

Lymphoma

Lymphadenopathy

63
Q

Which parts of the mouth are minor salivary glands not found?

A

Minor salivary glands are not found within

gingiva and anterior part of the hard palate

64
Q

What kind of saliva do minor glands produce?

A

Serous minor glands are the von ebner glands below the sulci of the circumvallate and folliate papillae of the tongue

Ventral tongue has the glands of Blandin-Nuhn

Palatine and glossopalatine glands are pure mucous

65
Q

How does saliva assist with digestion?

A

It neutralizes esophageal contents

Dilutes gastric chyme

Forms food bolus

Breaks starch

66
Q

How are salivary gland structures organized?

A

From the of the capsule surrounding and
protecting the gland pass septa that subdivide
the gland into major lobes; lobes are further
subdivided into lobules. Each lobe contains
numerous secretory units consisting of
clusters of grape-like structures (the acini)
positioned around a lumen

67
Q

What do seromucus cells do? How is their structure organized for this?

A

They secrete polysaccharides.

they have specialized secretory organelles such as RER and prominent golgi apparatus. (Carbohydrate moieties are added) and secretory granules are released via exocytosis.

68
Q

How is the secretory process different in serous cells compared to other cells?

A

The secretory process is continuous but cyclic

69
Q

What are the important zones and structures in the serous cells?

A

There are complex foldings of cytoplasmic membrane

The junctional complex consists of:

Tight junctions (Zonula occludencs) -> Fusion of outer cell layer

Intermediate junction (Zonula adherens) -> Intercellular communication

Desmosomes -> Firm adhesion

70
Q

What do mucous cells do? How is their structure organized for their function?

A

Produce, store, and secrete proteinaceous material: Smaller enzymatic component

Lots of golgi for post translational modification of saliva to create mucins.

RER is less prominent as well as having less interdigitations.

Less mitochondria

71
Q

How is the macromolecular component of saliva produced?

A

Synthesis of protein

RER, Golgi apparatus

Ribosomes -> RER -> Postranslational modification -> Golgi apparatus -> Secretory granules

Exocytosis

Endocytosis of the granule membrane

72
Q

What controls the production of fluid and electrolytes in saliva?

A

Parasympathetic innervation due to ACh binding to muscarinic receptors:

Activation of phospholipase -> IP3 -> Release of Ca -> Opening of channels K+, Cl-, Na+ in

Norepinephrine via alpha-adrenergic receptors results in substance P activation.

73
Q

What do striated ducts do to saliva secretions?

A

They modify the secretion (Hypotonic solution = low sodium and chloride and high potassium)

74
Q

How is ductal modification regulated?

A

Autonomic nervous system

Striated and terminal ducts do most of the regulation

Modification takes place via reabsorption and secretion of electrolytes

Final product is hypotonic

Rate of salivary flow is also regulated by these ducts (High: Sodium and chlorine up; potassium down)

75
Q

Which saliva flow rate is more significant in correlation with symptoms of xerostomia?

A

Unstimulated whole saliva flow rate is more likely to correlate with symptoms of xerostomia than stimulated flow rates.

76
Q

What are the oral problems associated with xerostomia?

A

Mucosal dryness

Liability to dental decay

Liability to gingival inflammation

Possible fungal infection

Loss of denture retention

Salivary gland infection

Taste abnormalities

77
Q

What oral problems are associated with oral mucosal dryness?

A

Dysarthria

Dysphagia

Mucosal adhesion

Stringy saliva

78
Q

What kind of gingival problems are associated with xerostomia?

A

Acute gingivitis

Chronic gingivitis

Desquamative gingivitis

79
Q

What infections are associated with xerostomia?

A

Bacterial sialadenitis

Oral candidosis

80
Q

What are the types of oral candidosis?

A

Pseudomembranous candidosis

Angular cheilitis

Denture-induced stomatitis

Median rhomboid glossitis

Erythematous candidosis

81
Q

What salivary gland is most commonly affected by bacterial sialadenitis?

A

The parotid

82
Q

How does xerostomia affect taste sensation?

A

Causes loss of taste or a bitter taste

83
Q

How does xerostomia cause denture problems?

A

Causes loss of retention of upper denture

Occasional traumatic oral ulcers result

Denture-induced stomatitis

84
Q

What causes xerostomia related salivary gland enlargement?

A

Sjogren’s-related inflammation
Sialadenitis
Lymphoma (Sjogren’s)
Lymphadenopathy (parotid)

85
Q

What are some common oral features seen in patients with xerostomia?

A

Difficulty in mouth opening (trismus)

Telangiectasia

Oral ulceration

Mucosal white patches

Neuropathies

86
Q

How are salivary gland problems investigated?

A

Sialography

Ultrasound

Ultrasound-guided fine-needle or
medium needle biopsy

Sialography

CT (+/-sialography)

MRI (+/-) sialography

99mTc-pertechnetate scintigraphy

Labial gland biopsy

Serology