Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gastrointestinal > Session 5 - Functions of the stomach > Flashcards

Session 5 - Functions of the stomach Flashcards

1
Q

What are the basic functions of the stomach?

A
  • Receive food (short term storage)
  • Disrupt food (contractions)
  • Continue digestion (mainly proteins)
  • Disinfect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the basic structure of the stomach?

A

Superior > Inferior

  • Oesophageal entry
  • Cardia
  • Fundus
  • Body
  • Antrum
  • Pylorus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the characteristics of the stomach?

A
  • Simple columnar epithelium
  • Mucosa/submucosa in folds - Rugae
  • Gastric pits
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the gastric pits and their functions?

A

Epithelial pits, containing specialised cells.

  • Mucous cells
  • Parietal cells
  • chief cells
  • G cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the muscle layers of the stomach.

A

Inner oblique
Middle circular
Outer longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the shape of the stomach affect the chyme?

A

Larger (proximal) to smaller (distal)

Separates the contents - lumps left behind.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is food moved through the stomach?

A

Strong peristalsis.
Proximal to distal. (every 20 seconds)
Liquid chyme ejected into duodenum 3 times per minute.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the orad and caudad regions of the stomach?

A

Orad - upper stomach

Caudad - Lower stomach

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

How does the stomach expand when food is eaten?

A
  • Vagally mediated relaxation of orad stomach (when food sensed in oesophagus)
  • Rugae can expand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is it important for the stomach to extend when food is eaten?

A

Prevents an increase in intra-gastric pressure, which prevents reflux of stomach contents during swallowing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which cells secrete which products in the stomach?

A 
Parietal cell = HCL + intrinsic factor
G Cell = Gastrin
Enterochromaffin like cell = Histamine
Chief cell = Pepsinogen
D Cell = Somatostatin
Mucous cells = Mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which products are mostly secreted in the cardia?

A

Mucus secretions

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

What is mostly secreted by the fundus/body?

A

Mucus, HCL, pepsinogen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which substances are secreted at the pylorus?

A

Gastrin, somatostatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which hormones control HCl production?

A 
Parietal cell
Stimulated by:
-Gastrin
-Histamine
-ACh
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Signals from which nerve to the stomach would increase HCl secretion?

A

Parasympathetic - Vagus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What stimulates G-cells at the stomach to secrete gastrin?

A

Presence of peptides/amino acids in stomach lumen.

Vagal stimualtion (ACh, Gastrin-releasing peptide GRP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is HCl secretion inhibited in the stomach?

A
  1. pH drop when food leaves stomach (food is buffer)
  2. Low pH activates D cells - secrete somatostatin
  3. Somatostatin inhibits G cells. (and enterochromaffin cells) less gastrin, less histamine)
    - thus less H+, less gastrin
  4. Stomach distension reduces, thus reduced vagal activity.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the three phases of digestion?

A
  • Cephalic
  • Gastric
  • Intestinal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is cephalic digestion?

A

a) Parasympathetic stimuli (smelling/ tasting/ chewing/ swallowing) (30% of HCl)
- Causes direct stimulation of parietal cells by vagus.
- Stimulation of G cells by vagus.

b) Anticipating food = increases gastric motility slightly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does gastric digestion cause digestion of food?

A

60% total HCl
- Distension of stomach - vagal stimulation
=stimulate parietal / G cells

-Presence of amino acids / peptides
=stimulate G cells

-Food acts as buffer
=removes inhibition on gastrin production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What role does the enteric nervous system and gastrin have on the stomach?

A

Cause strong smooth muscle contractions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does intestinal digestion cause?

A

10% of HCl production

- Chyme initially stimulates gastrin secretion (partially digested proteins in duodenum)

24
Q

How does chyme in the intestines slow stomach digestion?

A
  • The presence of lipids activate enterogastric reflex, which reduces vagal stimulation to stomach.
  • Chyme stimulate CCK and secretin, helps suppress secretion.
25
Q

Which cells in the stomach protect it from the highly acidic environment?

A

Mucus and HCO3- secretion by:

  • Surface mucus cells
  • Neck cells in gastric glands

Forms thick alkaline viscous layer, which adheres to epithelium, keeping it at a higher pH.

26
Q

Which other defenses does the stomach have to protect from the damaging acid effects?

A
  • High turnover of epithelial cells, keeping it intact.

- Prostaglandins - maintain mucosal blood flow and nutrient supply.

27
Q

Which things can breach the stomach’s surface epithelial defences?

A
  • Alcohol: dissolves mucus layer
  • Helicobacter pylori: Chronic active gastritis
  • NSAIDS: Inhibits prostaglandin
28
Q

What is dyspepsia?

A

Indigestion!
Affects up to 40% adults per year.
Impaired digestion in stomach, usually short term.

29
Q

What is gastro-oesophageal reflux disease? What are some symptoms?

A 
When stomach contents reflux into oesophagus, causing acid to affect the lower oesophagus (irritate or damage)
Symptoms:
-Heartburn
-Cough
-Sore throat (high up reflux)
-Dysphagia
30
Q

What is barret’s oesopagus?

A

Metaplasia of squamous epithelium of oesophagus to columnar (gastric) epithelium, due to chronic gastro-oesophageal reflux disease.

31
Q

What can treat gastro-oesophageal reflux disease?

A

Lifestyle: weight, meal time changes, sleeping more upright.

Pharmacological: Antacids, H2 agonists, Proton pump inhibitors.

Surgery: rare - make a sphincter (from fundus)

32
Q

What can treat gastro-oesophageal reflux disease?

A

Lifestyle: weight, meal time changes, sleeping more upright.

Pharmacological: Antacids, H2 agonists, Proton pump inhibitors.

Surgery: rare - make a sphincter (from fundus)

33
Q

What is acute gastritis, and what are its causes?

A

Acute mucosal inflammation of stomach.

  • Heavy NSAID use
  • Lots of alcohol
  • Chemotherapy
  • Bile reflux
34
Q

What are symptoms of acute gastritis?

A
  • Asymptomatic
    OR
  • Pain, nausea, vomiting (occasional bleeding can be fatal)
35
Q

What is chronic gastritis, and what causes it?

A

Chronic mucosal inflammation.
- H-pylori infection
- Autoimmune: e.g. antibodies against parietal cells
(Can cause pernicious anaemia)

36
Q

What is pernicious anaemia?

A

Anaemia caused by lack of intrinsic factor secretion in stomach due to loss of parietal cells. (maybe due to gastritis).
This causes reduced vitamin B12 uptake.

37
Q

What are symptoms of chronic gastritis cause by H-pylori?

A
  • asymptomatic or similar to acute.
  • may have symptoms due to complications:
    peptic ulcers, adenocarcinoma, MALT lymphoma
38
Q

What are the symptoms of autoimmune chronic gastritis?

A
  • Symptoms of anaemia
  • Glossitis (inflammation of the tongue)
  • Anorexia
  • Neurological symptoms
39
Q

What are the symptoms of autoimmune chronic gastritis?

A
  • Symptoms of anaemia
  • Glossitis (inflammation of the tongue)
  • Anorexia
  • Neurological symptoms
40
Q

What are peptic ulcers?

A

Defect in gastric/duodenal mucosa.

Must extend through muscularis mucosa.

41
Q

Where are peptic ulcers most common?

A

First part of the duodenum.

also common in lesser curve of stomach

42
Q

What are the most common causes of peptic ulcer disease?

A
  • Stomach acid
  • H-pylori
  • NSAIDS
    (smoking can cause relapse)
    (Massive physiological stress e.g. burns)
43
Q

Which symptoms would be found with peptic ulcer disease?

A
  • Epigastric pain: burning/gnawing
    following meals, or often at night.

-Serious symptoms:
bleeding/ anaemia
early satiety (fullness)
Weight loss

44
Q

What is functional dyspepsia?

A
  • Symptoms of ulcer disease

- Peristalsis/ sensation is disturbed, but with no clear physiological reason.

45
Q

Which clinical tests or scans can be performed in diagnosing gastric pathology?

A
  1. Upper GI endoscopy (biopsies)
  2. Urease breath test (urea breath test)
  3. Erect chest X-ray
  4. Blood test (anaemia etc)
46
Q

What is the urease breath test?

A

Urea breath test.
Used to detect if H-pylori present

(as it can break down urea to ammonia and CO2)
(radio labelled urea taken, then breath tested)

47
Q

How are peptic ulcers treated?

A 
- Eradicate H-pylori
TRIPLE THERAPY
1) PPI
2) clarithromycin
3) Amoxicillin

Stop NSAIDS
Endoscopy for bleeding ulcers

48
Q

How do H2 blockers work to reduce peptic ulcers?

A

Histamine antagonist
Block action of histamine at parietal cells.
This reduces proton secretion.

49
Q

Which proton pump inhibitor is most commonly given?

A

Omeprazole

50
Q

Name two H2 blockers used for ulcers.

A

Cimetidine

Ranitidine

51
Q

How is H-pylori spread? How does it remain in stomach?

A

Oral to oral, or faecal oral.
- Helix, gram -ve
- Flagellum = good motility
(lives in mucus layer, adhering to epithelium)

52
Q

How does H-pylori cause stomach damage?

A
  • Releases cytotoxins
  • Expresses endotoxins, like urease, which creates ammonia. Ammonia is toxic to epithelia.
  • Promotes inflammatory response (self injury)
53
Q

If found only in the antrum, what effect does H-pylori have?

A

Duodenal ulceration

54
Q

If H-pylori colonisation was in the antrum, and body of the stomach, what would be the symptoms?

A

Asymptomatic

55
Q

When may H-pylori lead to cancer?

A

If colonisation is predominantly in the body of the stomach.

Gastrointestinal (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions