4. Stomach And Pathology

Question 1

Epithelium above and below pyloric sphincter

Answer 1

Oesophagus- stratified squamous
Stomach- simple columnar

Question 2

What causes receptive relaxation of proximal stomach?

Answer 2

Peristalsis in oesophagus, alerts stomach somethings entering

Question 3

Which part of diaphragm contributes to pyloric sphincter?

Answer 3

Crural part

Question 4

In receptive relaxation, what distends?

Answer 4

Fundus

Question 5

Is upper stomach more muscular than lower?

Answer 5

No

Question 6

What are gastric pits made from?

Answer 6

Invaginations of stomach epithelia

Question 7

How many gastric glands per gastric pit?

Answer 7

1 or multiple

Question 8

Compare the resting and active states of parietal cells

Answer 8

Resting
-tubulovesicles containing proton pumps not associated with apical membrane
-lack K+ permeability

Active
-tubulovesicles in contact with apical membrane
-K+ channelsand proton pumps brough together
-cannaliculi and microvilli on apical membrane increase SA

Question 9

What receptor does gastrin stimulate on parietal cells? How?

Answer 9

CCK, similar structures

Question 10

Stimulation of entero-chromaffin like cells (ECL)

Answer 10

-vagal by ACh
-gastrin from G cells

Question 11

Explain histamine stimulation in parietal cells

Answer 11

-Either vagal or gastrin acting on CCK receptors stimaultes ECL cells to produce histamine
-Histamine acts on H2 receptors of parietal cells to increase acid production

Question 12

Describe alkaline tide in relation to HCl production in parietal cells

Answer 12

-HCO3- is transported out of parietal cell into blood via anion anti-port protein, whilst Cl- goes into parietal cells
-this creates an alkaline tide in blood
-Cl- combines with H+ from parietal cell in the lumen of stomach

Question 13

How is delayed gastric emptying a risk factor for gastro-oesophageal reflux disease?

Answer 13

Sustained increased pressure overcomes the lower oesophageal sphincter

Question 14

What is a hiatus hernia? How does it form?

Answer 14

In people with GORD, part of stomach can herniate through diaphragm into thorax, so LOS now in thorax
-loses crural muscle action on sphincter, so reflux a lot

Question 15

Name 3 things that help the LOS

Answer 15

1. Muscles: intrinsic and diaphragm
2. Right crus, pulls tighter when pressure higher
3. Acute angke of oesophageal entry to stomach, orevents reflux straight back up

Question 16

What must an ulcer pass through to class as an ulcer?

Answer 16

Muscularis mucosae

Question 17

Name 6 lifestyle changes to manage GORD

Answer 17

1. Weight loss
2. Avoid trigger foods
3. Eat smaller meals
4. Dont eat then sleep
5. Decrease alcohol and caffeine
6. Stop smoking

Question 18

Describe the surgery for GORD

Answer 18

Fundoplication
-fundus wrapped round back of oesophagus, anchors it below diaphragm to help sphincter mechanism

Question 19

What layer of stomach is inflamed in gastritis?

Answer 19

Mucosa

Question 20

In gastritis, what cells could be seen in lamina propria on histology?

Answer 20

Neutrophils

Question 21

Pathological changes in acute gastritis

Answer 21

-epihtelial damage
-epithelial hyperplasia
-vasodilation = angry looking
-neutrophil response

Question 22

Pathological changes in chronic gastritis

Answer 22

-lymphocytes invade lamina propria
-glandular atrophy
-Fibrotic changes
-Metaplastic changes

Question 23

Explain how autoimmune chronic gastritis can cause pernicious anaemia

Answer 23

-autoimmune antibodies to parietal cells, lose parietal cells
-less acid and intrinsic factor
-less absoroption of B12
-can cause megaloblastic anaemia as DnA synthesis halted in RBCs, so abnormally large cytoplasm

Question 24

Symptoms of autoimmune chronic gastritis take time. What are they?

Answer 24

-anaemia
-neurological
-anorexia
-glossitis

Question 25

Whats meant by H pylori being microaerophilic?

Answer 25

Needs some O2 but less than atmospheric, so stomach is perfe t level

Question 26

Features of H pylori that enable its survival

Answer 26

-flagellae -chemotaxis - under mucous layer of epithelium -adhesins - fix to epithelium and resists peristalsis

Question 27

Explain different products made by H pylori causing gatsritis

Answer 27

-urease: converts Urea and H2O to CO2 and ammonia, ammonia damages stomach epithelium -cytotoxin associated gene A gets into epithelia and stimulates IL-8 = inflammation -Vacuolating toxin A is toxic to epithelium

Question 28

Compare effects of H pylori in antrum vs body/fundus

Answer 28

Antrum: -G cells overactive so parietal cells increase number and acid - hyme leaving stomach is more acidic Body/fundus -atrophy of parietal cells -precursor to dysplasia

Question 29

Is colonisation of antrum and body by H pylori asymptomatic?

Answer 29

Yes

Question 30

Explain process of diagnosing H pylori

Answer 30

Urease breath test -patient ingests urea enriched with C13 -if urease oressnt, C13 converted to COW -CO2 excreted in breath and would comtain isotope C13

Question 31

Treatment for eradication of H pylori

Answer 31

-PPI -2x antibiotics (clarithromycin and metronidazole) 7 days

Question 32

Compare the following characteristics for gastric and duodenal ulcers -incidence -age -blood group -acid levels -H pylori

Answer 32

- 1:3 -increase/up to 35 -A vs O -could be low/ could be high -70% vs 95-100%

Question 33

Where do chronic ulcers develop?

Answer 33

Mucosal junctions e.g. antrum meets body, antrum meets small intestine

Question 34

Effects of scar tissue formed from peptic ulcer disease

Answer 34

Narrows stomach lumen, pyloric stenosis so vomiting

Question 35

How does haematemesis happen with ulcers of duodenum?

Answer 35

-ulcer can erode into gastroduodenal artery -blood fills stomach, vomit it -or could be partly digested and excreted as malaena

Question 36

Management of PUD if active bleeding

Answer 36

Endoscopy inject adrenaline and cautery

Question 37

Management of PUD with no active bleeding

Answer 37

H pylori positive -eradicate H pylori first via PPI and 2 antibiotics H pylroi negative -stop exacerbating meds -can add in PPIs to offset meds if cant stop them