GI PHYSIOLOGY 1 Flashcards
(27 cards)
List some of the functions of the stomach
Store food
Mix food
Dissolve
Continue digestion
Kill microbes
Secrete proteases
Secrete intrinsic factor
Activateproteases
Lubricate
Mucousal protection
what are some of the key cell types in GI
Parietal cells
Chief cells
mucosal cells
Enteroendocrine cells
what cell secretes gastric acid
parietal
list 3 phases of digestion in order
cephalic, gastric, intestinal
Cephalic phase is Parasympathetic or sympathetic
parasympathetic
Sight, smell, taste and chewing ar apart of which digestive phase
cephalic
which nerves are involved in cephalic phase
Facial
Vagus
Glossopharyngeal
in the cephalic phase what neurotransmitter is released from the plexus neurones
Acetylcholine
in the cephalic phase what does the facial nerve stimulate
saliva secretion
what is the main result of the cephalic phase
inc in HCL
Stimulation of the _____ nerve excites postganglionic parasympathetic neurones in the stomach, which then release __________ onto parietal cells to stimulate acid secretion.
Vagus
Acetylcholine
Acetylcholine triggers release of ______ and ______
histamines
gastrin
Once food reaches the stomach, the _______ phase of digestion begins
gastric
what is the main result of gastric phase
inc in HCL
Define a peptic ulcer
breach in mucosal surface
list 4 causes of peptic ulcers
Helicobacter pylori infection
NSAIDS
Chemical irritants
Gastrinoma
List 4 defence routes for the gastric mucosa
Alkaline mucous
tight epithelial junctions
Feedback loops
Replacement of damaged cells
why could Helicobacter pylori cause a peptic ulcer
Bacterium secretes urease = urea and co2 –> NH3 + H+ = NH4+=elevated pH=damage of gastric epithelium
Causes inflammatory response
Mucosal defence is weakened
Why could NSAIDs cause peptic ulcers
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
How could bile salts cause peptic ulcers
Duodeno-gastric reflux causes acid to be regurgitated and damage/strip the mucous layer
Leads to reduced mucosal defence
How to treat a peptic ulcer caused by helicobacter pylori
eradicate the organism by
proton pump inhibitors
antibiotics (amoxic,tetracycl, clarithomy, metronidazo)
how to treat a peptic ulcer caused by NSAIDS
Prostaglandin analogues – misoprostol
Reduce acid secretion
approx how much HCL does the body prodiuce /day
2L
what pump is used ignorer to shuttle H+ ions in the stomach to make HCL
Gastric hydrogen potassium ATPase
H+/K+ATPase
