Stomach Physiology

Question 1

Incisura

Answer 1

Inflection point of the stomach

Question 2

Lesser Curve Stomach left/right

Answer 2

Right

Question 3

Saliva Stimulation

Answer 3

Sight, smell, taste of food

Acid in the oesophagus (predicts vomit coming up)

Question 4

Saliva Inhibition

Answer 4

Sleep

Sympathetic ANS

Question 5

4 Contents of Salvia

Answer 5

1. HCO3- = Basic
2. Mucin = Lube
3. Amylase = Starch -> Smaller Carbs
4. Lysozyme = Anti-bacterial

Question 6

Antrum Role

Answer 6

Grinding mill of stomach

Question 7

Pylorus Role Stomach

Answer 7

Regulates size of particles that pass to duodenum (must be small)

Question 8

Osmolaloity change of contents in stomach

Answer 8

Bolus -> Chyme
= More watery

Question 9

Control of Gastric Emptying

Answer 9

Feedback mechs from duodenum: Acid, fat, amino acids, osmolarity

Question 10

Rapid Gastric Emptying (eg. Diarrhoea, prokinetic drugs) causes

Answer 10

Food moves too quickly through stomach = not completely digested, chyme hyperosmolar

Question 11

Gastric Acid Functions

Answer 11

1. Sterilises stomach
2. Denatures proteins
3. Absorption of B12 and Iron

Question 12

Parietal Cell Function

Answer 12

1. H+ Cl- ion secretion to lumen
2. HCO3- into blood

Question 13

Parietal Cell secretion mechanism

Answer 13

H+/K+ Proton Pump

Carbonic anhydrase needed to catalyse HCO3- production

Question 14

Stomach pH during night

Answer 14

Lowest (1-2) as no dilution from food etc

Question 15

Stomach pH after eating

Answer 15

Highest (5-6) as buffered and diluted

Question 16

What protects gastric mucosa from acid

Answer 16

Mucous

Bicarbonate buffer

Question 17

ACh Role in Regulating Gastric Acidity

Answer 17

DECREASES PH / INCREASED ACID SECRETION

Stimulates
1. Parietal Cell release HCl
2. ECL Cell release histamine = stim parietal
3. G Cell release gastrin = stim parietal and ECL

Question 18

ECL Cells Secretion

Answer 18

Histamine

Question 19

Histamine Role Acidity

Answer 19

Paracrine activity = stimulates Parietal Cells to release ACh

Question 20

ECL Cell Location

Answer 20

Stomach Body

Question 21

G Cell Secretes

Answer 21

Gastrin

Question 22

G Cell Location

Answer 22

Stomach ANtrum

Question 23

Gastrin Function

Answer 23

Endocrine

Stimulates histamine release from ECL cells
Stimulates HCL release from Parietal Cells

Question 24

D Cell Secretes

Answer 24

Somatostatin

Question 25

D Cell Location

Answer 25

Antrum Stomahc

Question 26

Somatostatin Function

Answer 26

Inhibits Gastrin secretion (= decreased HCl secretion)

Question 27

3 Phases of Digestion

Answer 27

1. Cephalic 2. Gastric 3. Intestinal

Question 28

Cephalic Phase

Answer 28

Thought, sight, smell of food -> ACh released by Vagus Nerve -> Stimulation of G ECL Parietal -> HCl

Question 29

Gastric Phase

Answer 29

Distension of stomach body and antrum causes acid secretion Protein in antrum stimulates G cells -> gastrin -> HCL

Question 30

What occurs in stomach during intestinal phase of digestion

Answer 30

HCl in antrum -> D cells release somatostatin -> gastrin inhibited -> less HCl HCl in duodenum -> Secretin -> less HCl Proteins/fats in duodenum -> CCK -> less HCl

Question 31

Helicobacter Pylori impact on gastric acid

Answer 31

Increased secretion

Question 32

Chief Cell secretion

Answer 32

Pepsinogen

Question 33

Pepsinogen function

Answer 33

Cleaved in acid to become Pepsin

Question 34

Pepsin function

Answer 34

Hydrolysis of proteins

Question 35

How do you stop a gastric bleed

Answer 35

Must inhibit acid secretion, as otherwise acidic environment activates pepsin which destroys clot

Question 36

Prostaglandins Function

Answer 36

Protection / repair of gastric mucosa

Question 37

Are gastric ulcers pain better / wrose with food

Answer 37

Worse

Question 38

Are duodenal ulcers better / worse with food

Answer 38

Better

Question 39

Peptic Ulcer Symtpoms

Answer 39

Epigastric Pain Bleeding -> blood in stool Perforation Obstruction = swelling / scarring

Question 40

Treatment of Peptic Ulcer Disease

Answer 40

Proton Pump Inhibitors (Historically surgery to decrease acid secretion)

Question 41

Peptic Ulcer Disease Cause

Answer 41

Increased Acid - Helicobacter pylori Decreased prostaglandins - Aspirin - NSAIDs

Question 42

H pylori risk factors

Answer 42

Poor childhood living conditions = Devleoping world, low SES, Maori

Question 43

H pylori causes

Answer 43

Break down of stomach mucous barrier -> mucosa

Question 44

Achlorhydria

Answer 44

Low/no stomach acid

Question 45

How does H pylori impact duodenum

Answer 45

H pylori -> increased gastrin -> increased acid -> gastric metallisation -> H pylori can migrate into duodenum

Question 46

Treatment for H pylori

Answer 46

First line triple therapy (antibiotics)

Question 47

Gastric Cancer Two Types

Answer 47

Intestinal Diffuse

Question 48

Intestinal gastric adenocarcinoma

Answer 48

Antrum Glandular pattern

Question 49

Diffuse gastric adenocarcinoma

Answer 49

Gastric Wall No glandular formation