Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

DIG E > E2 The biology of dyspepsia > Flashcards

E2 The biology of dyspepsia Flashcards

1
Q

state some symptoms of dyspepsia

A
  • upper abdominal pain / discomfort
  • heartburn
  • gastric reflux
  • nausea
  • vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the problems of dyspepsia related to?

A

gastric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why does reflux of stomach acid cause burning and pain?

A
  • oesophagus has limited protection against gastric acid compared to the stomach lining
  • excess acid can cause tissue damage due to lack of thick mucus layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the name for acid-secreting cells in the stomach and where are they localised?

A
  • parietal cells
  • localised in a specific region in the stomach (fundus, upper half)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the majority of the stomach lined with?

A
  • simple epithelium (a single layer of epithelial cells)
  • these cells are called surface mucous cells
  • they secrete a layer of mucus that protects the lining of the stomach against acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where are their sphincters in the GIT that stop gastric acid being where it shouldn’t? what is this concept called?

A
  • 2 sphincters prevent excess acid in the intestine and oesophagus (lower oesophageal sphincter and pyloric sphincter)
  • this allows for compartmentilisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what 2 adaptations does the stomach epithelium have for protection against acid?

A
  • mucus
  • tight junctions between cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe and explain how mucus protects the gastric epithelium against gastric acid

A

mucous:
- glycosolated proteins form a thick, viscous, gel-like layer on surface of cells
- bicarbonate neutralises gastric acid

acid in the stomach does not easily mix with mucus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe and explain how tight junctions between mucous surface cells in the stomach help protect against gastric acid

A
  • protein structures restrict movement of ions and water between cells (limits and regulates transport)
  • prevents acid leaking through the epithelial layer
  • prevents damage to underlying tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

tight junctions divide the cell membrane of the stomach into 2 compartments, what are they?

A
  • apical (outside, towards the lumen)
  • basolateral (inside, facing the basement membrane)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

compare and contrast the structure of the stomach epithelium and the oesophageal epithelium

A

stomach
- simple columnar epithelium
- mucous cells cover most of the internal surface

oesophagus
- non-keratinised stratified squamous epithelium
- specialised goblet cells secrete mucus but the mucus layer is much thinner than the stomach’s due to having fewer goblet cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

compare and contrast the protection against gastric acid that the stomach and oesophagus epitheliums provide

A

stomach
- adequate protection against gastric acid

oesophagus
- less protection against gastric acid
- in people with GORD, tissues can be damaged or destroyed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

where are parietal cells located?

A
  • in gastric pits
  • there are about 100 gastric pits per square millimetre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

functions of gastric acid

A
  • helps with the conversion of pepsinogen to pepsin (functional enzyme that breaks down protein)
  • kills many types of bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

state the structures of the gastric pits in the stomach

A
  • mucus layer
  • mucous cell
  • parietal cell
  • other cell types eg. G cells, chief cells
  • connective tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

function of G cells

A

produce gastrin

17
Q

function of chief cells

A

produce pepsin

18
Q

what is acid secretion stimulated by?

A

extracellular signals:
- histamine
- acetylcholine
- gastrin (peptide hormone)

  • these signals can activate parietal cells by interacting with receptors localised on the basolateral membrane
19
Q

why is a lot of gastric acid able to be secreted in the stomach?

A

there are lots of parietal cells next to each other in the gastric pits

20
Q

what does histamine bind to when stimulating gastric acid secretion?

A

H2 receptor

21
Q

what does ACh bind to when stimulating gastric acid secretion?

A

M3 receptor

22
Q

what does gastrin bind to when stimulating gastric acid secretion?

A

CCK2 receptor

23
Q

hydrochloric acid is secreted into the stomach through intermediate steps, what are they?

A
  • uptake of carbon dioxide by diffusion
  • hydration of carbon dioxide by carbonic anhydrase enzyme to produce proton and bicarbonate
  • apical side is where H+ is exported by the gastric proton pump (orange circle) in exchange for K+
  • basolateral side is where uptake of Cl- occurs in exchange for bicarbonate ions
24
Q

what transport mechanisms can be seen in this image of a parietal cell?

A

ion channels
solute transporters
uniporters
symporters
antiporters
ion pumps
diffusion

25
Q

what kind of receptor is a H2 receptors?

A

GPCR
histamine binds to it at parietal cell basolateral side

26
Q

what is Pepcid?

A
  • H2 receptor antagonist that can be prescribed
  • inhibits H2 receptor and prevents secretion of HCl
27
Q

where can famotidine bind and what does this binding cause?

A
  • binds in the histamine binding pocket of the H2 receptor
  • if famotidine binds, it stops histamine binding and having an effect
  • inhibits acid secretion
28
Q

describe how H2 receptor antagonists can be used to treat dyspepsia

A
  • prevent binding of histamine
  • the receptor then can’t be activated by histamine
  • conformational change of protein leads to a different shape despite the antagonist binding in a similar location
29
Q

what happens at E1?

A

hydrogen ions being readily transported into the contents of the stomach

30
Q

what happens at E2?

A

where transport of potassium occurs

31
Q

describe more about this image such as what state is more common and what PPIs do to these configurations

A
  • transition between these states continuously
  • PPIs lock proton pumps in the E2 configuration so it can’t transport any hydrogen ions across the apical membrane
32
Q

what path do PPI drugs follow in the body for them to have an affect on gastric acid secretion?

A

stomach
duodenum
blood
parietal cells

33
Q

describe the behaviour of PPI tablets in the stomach

A
  • pH 1-2
  • protected by enteric coating, remains as prodrug
  • doesn’t target parietal cells at this stage, it bypasses them
34
Q

describe the behaviour of PPI tablets in the duodenum

A
  • pH 6-6.5
  • uncharged
  • easily absorbed
35
Q

describe the behaviour of PPI tablets in the blood

A
  • pH 7.4
  • uncharged
  • systemic circulation
36
Q

describe the behaviour of PPI tablets in the parietal cells

A
  • pH ≤ 2
  • ionised, forms active drug and reacts with target
  • targets parietal cells from basolateral side so need to go through systemic circulation to reach basolateral side
  • when activated, PPI limits proton transfer

DIG E (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions