Salivary and Gastirc Secretory Functions Flashcards

1
Q

is saliva hyper or hypotonic

A

hypotonic

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2
Q

what type of control is saliva under

A

neuronal not hormonal

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3
Q

do hormones have an influence on saliva

A

they can modify it

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4
Q

what are the functions of saliva

A

taste, lubrication, protection, digestion, speech

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5
Q

What are the main components of saliva

A

water, mucus, alpha amylase, lingual lipase, ribonuclease, lysozyme, lactoferrin, lactoperoxidase, IgA, Bicarb

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6
Q

what are the functions of water and mucus in the saliva

A

dissolving, tasting and swallowing food. lubricaitons and makes a cohesive bolus

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7
Q

what is the function of alpha amylase in saliva

A

card digestion, breaks the alpha 1-4 bonds

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8
Q

What is the role of lingual lipase in saliva

A

fat digestion, hydrolysis of dietary lipid

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9
Q

what is the role of lysozyme in saliva

A

antibacterial, innate and aquired immunity

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10
Q

what is the role of lactoferrin in saliva

A

chelates iron

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11
Q

what is the role of bicarb in saliva

A

minimize tooth decay and neutralize refluxed gastric acid into lower esophagus

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12
Q

what is the primary secretory products of acini and duct cells

A

alpha amylase, mucus and ECF

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13
Q

What do acini cells secrete

A

saliva H2O na Cl K HCO3 and amylase

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14
Q

what is the role of myoepithelial cells in salivary glands

A

motile, contract to expel saliva

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15
Q

what is the role of ducta cells in salivary glands

A

modify secretion by modifying electrolytes
Na Cl reabsorbed
K HCO3 secreted

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16
Q

what is the role of the striated duct epithelium tight junction in salivary glands

A

H2O cannot leave duct

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17
Q

What is the ufunctional unit of the salivary gland

A

salivon

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18
Q

At low rates of secretion describe saliva

A

hypotonic, high K, low NaCl

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19
Q

at high secretion levels describe saliva

A

osmolality increases, high HCO3, high pH

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20
Q

Salivary duct cells produce a hypotonic fluid that usually has what composition of electrolytes

A

low NaCl

rich KHCO3

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21
Q

What are the steps for Na reabsorption in salivary glands

A

Na enters through epithelial Na Channels

NaK ATPase pump extrudes Na

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22
Q

What are the steps for Cl reabsorption in salivary glands

A

Cl enters through Cl HCO3 exchanger

Cl exits through basolateral Cl Channels

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23
Q

Where is HCO3 secreted by salivary glands

A

apical Cl-HCO3 exchanger

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24
Q

how is K secreted by salivary gland cells

A

uptake of K though Na K ATPase

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25
Q

Can water pass through epithelial cells of the salivary glands

A

no

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26
Q

Which parts of ANS controls flow of salivary gland secretions

A

SAN and PAN

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27
Q

Which branch of ANS has more control over salivary glands

A

PAN

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28
Q

Describe what SAN stimulate promotes in salivary glands

A

major B R so secrete protein, cAMP

minor alpha R to secrete fluid, IP3

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29
Q

describe what PAN stimulates in salivary gland

A

M3 R to secrete fluid, IP3
vasodilation to surrounding vessels
activation of acinar and duct cell transporter

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30
Q

What hormones have an effecton salivary composition

A

ADH and aldosterone can modify Na K levels

Kallikrein makes bradykinin (vasodilator)

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31
Q

What activates the ANS to salivary glands

A

taste, sound, smell

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32
Q

What inhibits ANS to salivary glands

A

sleep, fear, antidepreseant meds, dehydration, fatigue

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33
Q

how do you treat someone with excessive drooling

A

anticholinergics and surgical removal of sublingual glands

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34
Q

What is Xerostomia

A

dry mouth due to absence of saliva production

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35
Q

what can cause xerostomia

A

buccal infections, dental caries, drugs, radiation, autoimmune disease

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36
Q

What is Sjogrens syndrome

A

autoimmune to salivary and lacrimal glands resulting in decreased saliva and tear production
difficuly swallowing, speeech etc

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37
Q

How does cystic fibrosis affect salivary glands

A

elevated Na Ca and protein in saliva, sweat, pancreatic fluid and bronchial secretion
lack CFTR or chloride transporter

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38
Q

How does addisons affect salivary gland

A

increase Na in saliva, dereased reabsorption

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39
Q

how does Primary aldosteronism and Cushings affect salivary glands

A

decrease Na in salive, increased reabsorption (salivary NaCl is zero with increased K levels)

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40
Q

How can digoxin therapy affect salivary glands

A

increase Ca and K in saliva

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41
Q

How can parkinsons and tumors of the mouth and esophagus affect saliva

A

increased production due to unusual local reflexes and increased neuro stimulation

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42
Q

Is stomach fluid hypo, iso or hypertonic

A

isotonic

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43
Q

What does the proximal portion of the stomach secrete

A

HCl, Pepsinogen, IF, Mucus, HCO3, water

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44
Q

what does the distal portion of the stomach secrete

A

gastrin, somatostatin

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45
Q

Which part of the stomach has endocrine and paracrine actions

A

the distal

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46
Q

What are the types of secretory epithelial cells in the stomach

A

superficial, mucus neck cell, stem cell, parietal, chief and endocrine

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47
Q

What do the mucus neck cells in the stomach secrete

A

Mucus and bicarb

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48
Q

whar do the parietal cells in the stomach secrete

A

HCl, IF

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49
Q

What is IF required for in stomach

A

required for Vit B12 absorption in ileum

50
Q

what is another name for Vit B12

A

cobalamine

51
Q

What do the chief cells in the stomach secrete

A

pepsinogen and renin

52
Q

what do the endocrine cells in the stomach secrete

A

enterochromaffin like cells secrete histamine
G cells- gastrin
D cells- somatostatin

53
Q

Whey are Oxyntic glands in the stomach

A

fundus and body

54
Q

What type of secretory cells are in the oxyntic glands

A

parietal (oxyntic)
peptic (chief, zymogenic)
mucus

55
Q

what do parietal cells secrete

A

HCl for protein breakdown, pepsinogen

IF for vit B12 absorption

56
Q

What do peptic,c hief cells secrete

A

Pepsinogen/zymogens- converted to pepsin

chymosin, gastric lipase

57
Q

What do mucus cells secrete

A

mucus both thick and thin

58
Q

where in the stomach can you find pyloric glands

A

antrum and pyloric region of stomach

59
Q

What type of cells are in pyloric glands

A

G cells and Mucus cells

60
Q

What do G cells secrete

A

Gastrin which stimulates parietal cells HCl and peptic cells (pepsinogen)

61
Q

what do mucus cells secrete

A

mucus thin and thick

62
Q

how often is the stomach mucosa replaced

A

every 3 days

63
Q

What cells in the stomach are responsible for secretion in between meals

A

the non-parietal cells that maintain high NaCl and low H and K

64
Q

what cells are responsible for stomach secretions after meals

A

parietal cells to maintain high H Cl

and low Na K

65
Q

Describe “alkaline tide” of stomach

A

increased pH of venous blood leaving stomach after a meal because H+ has increased secretion into the lumen so HCO3 is secreted to maintain neutrality

66
Q

What are the 3 mechanisms of direct stimulation of parietal cells

A

ACh releaed from vagus binds M3 R
Histamine recleased binds H2 R
Gastrin released binds CCKb R

67
Q

Describe the indirect stimulatroy mechanisms of parietal cells

A

ACh released from vagus binds M3R on ECL and release histamine
Gastrin released bund to CCKb on ECL to released histamine
Histamine released then binds H2 R on parietal cells

68
Q

Which agonist of the parietal cells is most potent

A

gastrin

69
Q

What are some inhibitors of parietal cells and how do they block the cells

A

somatostatin and PGs
somatostatin binds to SST T
PGs ving to PGs R

70
Q

The release of Ach to parietal cells is controlled by what

A

neuronal

71
Q

the release of gastrin on parietal cells is controlled how

A

hormonally

72
Q

the release of histamine on parietal cells is controlled by

A

paracrine

73
Q

What stim and inhibits release of somatostatin

A

pH dependent

inhibited by vagal stimulation

74
Q

What is the effect of Gastric inhibitory peptide

A

inhibits gastrin and acid in duodenum and jejunum

75
Q

What is natures antacid

A

secretin, inhibits gastrin and acid release in duodenum

76
Q

What cells secrete CCK

A

I cells of SI

77
Q

What cells secrete secretin

A

S cells in SI

78
Q

What cells release GIP

A

K cells in duodenum and jejunum

79
Q

What cells secrete Somatostatin

A

D cells of stomach and duodenum

and cells in pancreatic islets

80
Q

What are the stimuli for decrease in gastric secretions

A

distension of stomach ad it empties
accumulation of acid in the antrum and duodenum
fat acid hypertonicity and distension in duodenum

81
Q

What are the 3 phases of gastric secretions

A

Cephalic phase
Gastric Phase
Intestinal Phase

82
Q

What phase does most of the gastric secretion take place

A

gastric phase

83
Q

What is a vagotomy and what it it used for

A

cutting of vagus
inhibit gastric secretion and used to Tx peptic ulcers
side effects are diarrhea and delay in gastric emptying

84
Q

What is selective vagotomy

A

cutting vagal nn supplying parietal cells only

85
Q

What are the 3 hormones in the duodenum that inhibit acid secretion

A

secretin
GIP
CCK

86
Q

What structural component is responsible for peptic ulvers

A

damaged gastric mucosal barrier from over load of H+

87
Q

What are the 2 main signals for pepsinogen secretion

A

vagal by Ach

direct response to gastric acid

88
Q

How does IF help with vit B 12 absorption

A

bind into a complex and then bind to cubulin in the terminal ileum for R mediated endocytosis

89
Q

What could result from defective Vit B 12 absorption, or absent IF

A

defective RBC production,, pernicious anemia

90
Q

What is the function of the mucus secreted by surface cells

A

acts as diffusion barrier for H and pepsin, also traps HCO3 to titrate H and innactivate pepsin

91
Q

What happens if H penetrates into gastric epithelium

A

destorys mast cells and so histamine is released and there is great damage from inflammation PAFs LTs

92
Q

What are some substances that can lead to mucosal damage

A

alcohol
salicylates
H. pylori
Bile acids

93
Q

What does pepsin digest

A

proteins

94
Q

What is the prmiary stimulus for secretin release

A

acidic chym

95
Q

what are the general actions of secretin

A

increased HCO3 secretion

increase biliary and SI buffer system

96
Q

What is the main action of CCK

A

increase pancreatic enzyme secretion to break down small peptides and amino acids and fats

97
Q

What hormone increases pancreatic insulin secretion

A

GIP

98
Q

What is the main cause of peptic ulcers

A

H pylori

99
Q

How can aspirin cause ulcers

A

NSAID inhibit Cox-1 which forms PGs, so no protective PGs in gastric mucosa
it is a weak acid that is easily absorbed in low pH of stomach adn then causes histamine release and disruption of mucosal layer

100
Q

What is more common gastric ulcers of duodenal

A

duodenal

101
Q

What pathologies cause increased gastrin secretion

A

gastrinoma or zollinger-Ellison

102
Q

What is used to test gastric acid levels

A

pentagastrin challenge

103
Q

describe the difference between gasttrionmas and H pylori chornic infection on gastrin release

A

increase acid release in gastrinomas and decrease gastric acid release in chronic inflammation

104
Q

how does pernicious anemia affect gastrin secretion

A

lack of IF decreases H+ and somatostatin so now there is no inhibition of gastrin release so this increases while there is no H+

105
Q

What type of bacterium is H pyloric

A

gram negative

106
Q

What are the actions of H pylori on gut

A

high urease activity to neutralize acid and dmage epithelium
these damaged cells now increase acid secretion
results in inflammation and mucosal degredation

107
Q

t/F everyone iwth a gastric ulcer is caused by h pylori or has it too

A

True

108
Q

What factors strenghten the mucosal barrier

A
mucuc
HCO3
gastrin
PGs
epidermal growth factor
109
Q

What are types of antacids

A

NaHCO3 (alka-seltzer) or KHCO3

110
Q

what are H2 R blockers

A

rantidine (zantaz) and cimetidine (tagamet)

111
Q

What are proton pump inhibitos

A

omeparazole (prilosec)

112
Q

What are antibiotics used for H pylori infection

A

clarithromycin and cymxicillin or metronidazole

113
Q

What are surgical Tx for ulcers

A

vagotomy and anterctomy

114
Q

What are long term effects of proton pump inhibitors

A

pneumonia
clostridium difficile in gut
osteoporosis

115
Q

What is the drug dicyclomine and why don’t we use it

A

blocks Ach R, however no specific so does this everywhere in body

116
Q

Where is the primary saliva produced and where is it modified

A

produced in the end pieces called acini and is modified through th ducts

117
Q

does the saliva become hypotonic or hypertonic as it moves throughducts

A

more hypotonic

118
Q

All regulatroy control of salivation is from what

A

ANS

119
Q

What allows parietal cells to secrete acid

A

H K pump ATPase on apical side

120
Q

During the cephalic phase of secretion are the parietal cells directly or indirectly stimulate and how?

A

directly via Ach and gastrin release

121
Q

When the pH in the luminal contents of stomach drop below 3 what happens

A

somatostatin is released from D cells in antrum and oxyntic gland area