the oral environment Flashcards
1
Q
state the oral fluids
A
saliva, gingival crevicular fluid, oral bacteria, food debris and epithelial cells
2
Q
what are the 2 main functions of oral fluid?
A
protective and digestive
3
Q
in which ways does the oral fluid perform a protective function?
A
cleansing, mucosal protection, buffering, remineralisation, antimicrobial
4
Q
in which ways does the oral fluid perform a digestive function?
A
digestive enzymes, lubricates bolus for chewing and swallowing
5
Q
what may a reduced saliva flow cause?
A
caries in abnormal places (buccal and labial area), xerstomia
6
Q
name the 3 major pairs of salivary glands glands
A
parotid, sublingual and submandibular
7
Q
where are the minor salivary glands located?
A
buccal, labial, lingual, palatal
8
Q
what are the basic secretory units of salivary glands?
A
clusters of cells called acini
9
Q
which duct leads directly from the acini of salivary glands?
A
intercalated duct
10
Q
which duct leads directly from the intercalated duct?
A
striated duct
11
Q
where is all saliva produced by salivary glands gathered?
A
collecting duct
12
Q
which major salivary gland produces mixed secretions?
A
submandibular
13
Q
which major salivary gland produces serous secretion
A
parotid
14
Q
which major salivary gland produces mucous secretion
A
sublingual
15
Q
which minor salivary glands produce mucous secretion
A
buccal, labial, lingual and palatal
16
Q
which minor salivary gland produces serous and mucous secretions?
A
lingual
17
Q
where is gingival crevicular fluid produced?
A
the epithelium lining gingival crevice
18
Q
what may gingival crevicular fluid also be called?
A
secular fluid
19
Q
what increases the flow of gingival crevicular fluid?
A
inflammation (gingivitis)
20
Q
what is the average daily salivary flow?
A
500-700ml
21
Q
which salivary gland is the major contributor when sleeping?
A
submandibular
22
Q
which salivary gland is the major contributor when awake?
A
submandibular
23
Q
which salivary gland is the major contributor when stimulated?
A
parotid
24
Q
which factors affect unstimulated salivary flow rate?
A
state of hydration, previous stimulation, circadian and circannual rhythms, medication and salivary gland disease
25
what are the inorganic components of saliva and their % composition?
water (99.5%), ions (0.2%)
26
what are the organic components of saliva and their % composition?
mainly proteins (0.3%) and very little carbohydrates or lipids
27
which buffering ion concentration is greater at higher salivary flow rate?
bicarbonate
28
which ions are present in saliva?
fluoride, calcium and phosphate, thiocyanate, bicarbonate, phosphate
29
what is the function of the fluoride ion in saliva?
antibacterial, forms fluoroapatite, promotes remineralisation
30
what is the function of the calcium ion in saliva?
remineralisation
31
what is the function of the bicarbonate ion in saliva?
buffering
32
what is the function of the phosphate ion in saliva?
remineralisation and buffering
33
what is the function of the thiocyanate ion in saliva?
antibacterial
34
what are the salivary buffers?
bicarbonate, phospahtes, proteins, bacterial ammonia
35
describe the series of events that occur in acini cells to produce saliva
. increase in calcium opens calcium dependant potassium and chloride ion channels
. chloride ions cross the apical membrane into lumen of acinus
. sodium follows chloride across cell to maintain electroneutrality
. resulting osmotic gradient moves water
36
name the 13 main salivary proteins
amylase, lipase, cystatin, gusting, statherins, histatins, immunoglobin, lactoferrin, lactoperoxidase, lysozyme, plasma proteins, proline-rich proteins, mucoproteins
37
what type of protein is amylase?
enzyme
38
which 2 ions does amylase require?
chloride and calcium
39
what is another name for the lysozyme proteins produced in saliva?
muramidase
40
what is the general role of salivary amylase?
defence
41
what is the general role of salivary lysozymes?
non-specific defence
42
how do lysozyme carry out defence?
attack bonds in bacterial cell walls causing lysis
43
what is another name for lactoperoxidase in saliva?
sialoperoxidase
44
what type of protein is sialoperoxidase (lactoperoxidase)?
enzyme
45
what does lactoperoxidase in saliva do?
releases oxygen from hydrogen peroxide, and allows oxidation of thiocyanate to orodcude hypothiocyanate
46
which bacteria are intolerant to oxygen?
obligate anaerobes
47
what is the function of hypothiocyante?
antibacterial action
48
what do cystatins in saliva do and what is their function?
inhibit cysteine proteases, antimicrobial function
49
what are cysteine proteases?
proteins which breakdown proteins on amino acid cysteine side chain
50
which molecule does gustin require to function?
zinc
51
what is the function of the salivary protein gustin?
facilitate taste function by activating taste buds, produce bicarbonate buffer
52
what does the salivary proteins histatin do?
. inhibits calcium phosphate precipitation (calcium phosphate precipitation forms calculus) by allowing super saturation of calcium phosphate
. antimicrobial
. inhibits candida albicans and strep mutans
53
what compound is hydroxyapatite made from?
calcium phosphate
54
what type of protein molecules are immunoglobins?
antibodies
55
give an example of an immunoglobin?
IgA
56
which salivary protein has a short memory?
immunoglobin
57
what is the function of salivary immunoglobin?
specific immunity against bacteria
58
which salivary protein binds to iron?
lactoferrin
59
what is the function of lactoferrin?
takes away iron from oral environment and therefore from iron-requiring bacteria, antibacterial
60
where in the mouth is iron found?
gingiva
61
describe the structure of mucoproteins
polypeptide backbone with polysaccharide side chains
62
what do salivary mucoproteins do?
```
. bind to tooth and epithelial surfaces, when it binds conformation changes allowing more bacteria to bind
. protective role
. lubricative role
. forms primary pellicle
. promotes bacterial aggregation
```
63
what is the primary pellicle?
protein film on surface of enamel formed by selective binding
64
what is the function of salivary proline-rich proteins?
adsorb onto hydroxyapatite:
- acting as diffusion barrier
- decreasing mineral loss
- resist acid attack
- allow mineralisation
65
what is the function of salivary statherins?
. prevent precipitation of calcium phosphate by super saturation
. maintain high Ca for remineralisation and PO4 for buffering
. anticalculus action
66
give examples of plasma-derived proteins which have spilled over
proteins, blood group substances, ummunoglobins, hormones, drugs
67
name the 9 antimicrobial salivary proteins
cystatins, histatins, amylase, immunoglobin, lactoferrin, lysozyme, mucoproteins, lactoperoxidase, proline-rich proteins
68
name the 2 buffering salivary proteins
gustin, statherins
69
name the 3 digestive salivary proteins
amylase, lipase, lysozyme
70
name the lubricating salivary protein
mucoprotein
71
name the 2 remineralising salivary proteins
proline-rich proteins and statherins
72
what to responses control the secretions of saliva?
unconditioned and conditioned responses
73
define unconditioned responses
unlearned, innate
74
define conditioned responses
learned, acquired y association
75
what are the 2 types of conditioned responses that produce saliva?
mechanical and chemical
76
describe how saliva is produced by mechanical stimuli
. pressure on PDL/oral mucosa stimulates saliva from ipsilateral gland
77
describe how saliva is produced by chemical stimuli
gustation (tasting) or olfaction or common chemical sense triggers saliva
78
what does ipsilateral mean?
gland on same side
79
what is common chemical sense?
privative response to irritants or injury, mediated by nociceptors (respond to damage) in mucous membranes, contribute to taste of spices
80
what effect do parasympathetic nerves have on salivation and blood flow?
increased blood flow and salivation
81
what effect do sympathetic nerves have on salivation and blood flow?
increased salivation, decreased blood flow
82
name the 2 mechanism of salivary secretion
primary secretion in acinus and secondary modification in striated ducts
83
which cells secrete primary saliva
acini
84
which ducts modify saliva?
striated ducts
85
how is saliva modified by striated ducts?
bicarbonate and potassium secreted into saliva and sodium and chloride removed
86
what is saliva in relation to plasma?
hypotonic
87
how is bicarbonate formed?
CO2 + H2O in the presence of carbonic anhydrase
88
approximately how much saliva is in the mouth?
1.1ml
89
is the saliva film in motion or static?
motion
90
where is saliva film velocity flow lowest?
labial, buccal regions
91
where is saliva film velocity flow highest?
lower, lingual areas
92
how does saliva film velocity influence the incidence of caries?
cariogenic sugars are retained longer in regions where flow is lowest
93
where is the mouth is caries most common?
upper, labial regions
94
where is the mouth is calculus most common?
lower lingual regions
95
define incidence
no. within period of time
96
define prevalence
overall amount
97
define clearance
rate at which substances are removed from the mouth
98
in which 2 ways is clearance important for oral health?
. removal of harmful substances
| . retention of beneficial substances
99
how is removal of harmful substances increased?
high salivary flow rate
100
how is retention of beneficial substances improved?
low salivary flow rate
101
how do micro-organism generate acid?
metabolising sugars
102
what is a stephans curve?
a graph of the plaque pH change over time
103
what is occurring when plaque pH drops to a critical level?
demineralisation
104
at what pH are teeth remineralised?
approx pH 5.5
105
which bacteria species likes acid?
streptococci mutans
106
what is the main benefit to our oral health of chewing gum?
increases salivary flow
107
how does gum increase salivation?
stimulates mechanoreceptors on PDL
108
how does gum neutralise plaque acid?
increases bicarbonate content of saliva
109
why are sweetners not bad for our oral health?
they are not metabolised to acid by plaque bacteria
110
name some bulk caloric substances?
sucrose, fructose, glucose and lactose
111
are bulk caloric substances cariogenic?
yes
112
name some non-caloric/high-intensity sweetners
aspartame, cyclamates, saccharin, sucralose
113
name some low caloric sweetners
mannitol, sorbitol, xylitol
114
patients complain of dry mouth when salivary flow drops below?
50%
115
a reduction in salivary flow by 50% requires loss of what?
function of more than 1 major salivary gland
116
what may cause xerostomia?
side effect of drugs, radiotherapy, diseases
117
how does radiotherapy cause xerostomia?
it damages glands and epithelia
118
what may reduced salivary flow cause?
caries, oral disease, dysaesthesia, impaired oral function, diminished taste perception
119
what is the clinical name for burning mouth?
dysaethesia
120
what is caused as a result of reduced clearing?
loss of protective function
121
what can be used to treat xerostomia with functioning gland tissue?
drugs, chewing gum
122
what can be used to treat xerostomia with no functioning gland tissue?
saliva substituem containing mucins or cellulose
