GI PHYSIOLOGY 1

Question 1

List some of the functions of the stomach

Answer 1

Store food
Mix food
Dissolve
Continue digestion
Kill microbes
Secrete proteases
Secrete intrinsic factor
Activateproteases
Lubricate
Mucousal protection

Question 2

what are some of the key cell types in GI

Answer 2

Parietal cells
Chief cells
mucosal cells
Enteroendocrine cells

Question 3

what cell secretes gastric acid

Answer 3

parietal

Question 4

list 3 phases of digestion in order

Answer 4

cephalic, gastric, intestinal

Question 5

Cephalic phase is Parasympathetic or sympathetic

Answer 5

parasympathetic

Question 6

Sight, smell, taste and chewing ar apart of which digestive phase

Answer 6

cephalic

Question 7

which nerves are involved in cephalic phase

Answer 7

Facial
Vagus
Glossopharyngeal

Question 8

in the cephalic phase what neurotransmitter is released from the plexus neurones

Answer 8

Acetylcholine

Question 9

in the cephalic phase what does the facial nerve stimulate

Answer 9

saliva secretion

Question 10

what is the main result of the cephalic phase

Answer 10

inc in HCL

Question 11

Stimulation of the _____ nerve excites postganglionic parasympathetic neurones in the stomach, which then release __________ onto parietal cells to stimulate acid secretion.

Answer 11

Vagus
Acetylcholine

Question 12

Acetylcholine triggers release of ______ and ______

Answer 12

histamines
gastrin

Question 13

Once food reaches the stomach, the _______ phase of digestion begins

Answer 13

gastric

Question 14

what is the main result of gastric phase

Answer 14

inc in HCL

Question 15

Define a peptic ulcer

Answer 15

breach in mucosal surface

Question 16

list 4 causes of peptic ulcers

Answer 16

Helicobacter pylori infection
NSAIDS
Chemical irritants
Gastrinoma

Question 17

List 4 defence routes for the gastric mucosa

Answer 17

Alkaline mucous
tight epithelial junctions
Feedback loops
Replacement of damaged cells

Question 18

why could Helicobacter pylori cause a peptic ulcer

Answer 18

Bacterium secretes urease = urea and co2 –> NH3 + H+ = NH4+=elevated pH=damage of gastric epithelium

Causes inflammatory response

Mucosal defence is weakened

Question 19

Why could NSAIDs cause peptic ulcers

Answer 19

NSAID AKA non-steroid anti-inflammatory drugs

NSAIDS inhibit COX-1 (cyclo-oxygenase) which is needed for prostaglandin synthesis. Prostaglandins are needed for mucous synthesis, thus mucous defence is weakened

Question 20

How could bile salts cause peptic ulcers

Answer 20

Duodeno-gastric reflux causes acid to be regurgitated and damage/strip the mucous layer

Leads to reduced mucosal defence

Question 21

How to treat a peptic ulcer caused by helicobacter pylori

Answer 21

eradicate the organism by

proton pump inhibitors

antibiotics (amoxic,tetracycl, clarithomy, metronidazo)

Question 22

how to treat a peptic ulcer caused by NSAIDS

Answer 22

Prostaglandin analogues – misoprostol

Reduce acid secretion

Question 23

approx how much HCL does the body prodiuce /day

Answer 23

2L

Question 24

what pump is used ignorer to shuttle H+ ions in the stomach to make HCL

Answer 24

Gastric hydrogen potassium ATPase
H+/K+ATPase

Question 25

what does somatostatin (paracrine factor) act on to reduce acid production

Answer 25

parietal cells

Question 26

which paracrine factor allows activation of acid production

Answer 26

histamines

Question 27

what hormone activates acid production

Answer 27

Gastrin