GI Tract Flashcards
What are Parietal Cells?
Cells that secrete acids
Where does histamine come from
ECL enterochromaffin-like and bind to histamine 2 receptors - different to hayfever (h1)
What activate gastrin?
Milk, calcium, amino acids & small peptides
What is gastrin?
An acid secretor - release is controlled by neuronal transmitters, blood-bone mediators
What is somatostatin with regards to pariental cells?
Inhibitor of acid secretions
What happens if histamine secretion is increased?
An increase in acid secretions
What is a co-symporter?
When ion flow is in the same direction
For example with gastric acids - both chloride & potassium ions flow in the same direction
What do antacids do?
They neutralize gastric acids but don’t treat/prevent gastric ulcers
Raise gastric pH
Inhibit activity of peptic enzymes
What are side effects of antacids?
Wind
Diarrhoea
Constipation
What are H2 receptor antagonists?
Inhibit gastric acid secretion by blocking the H2 receptor on pariental cells
Block stimulated gastrin secretions
Promote healing of gastric ulcers
Treat GORD
Name types of H2 Receptors & side effects
Ranitidine
Famotidine
Nizatidine
Dizziness, muscle pain, slope is
Decreased libido
What is a PPI?
Blocks proton pump (H+/K+ATPase)
Long acting
Omeprazole causes irreversible block
Accumulate in parietal cells
Side effects of PPI
Diarrhoea, headache
Bone fracture risk- due to change in environment due to them accumulating in other cells - may impact calcium
What are used to treat H.Pylori?
PPI& 2 antibiotics
Triple Therapy -
Amoxicillin & metronidazole
Amoxicillin & clarithromycin
Other combos of antibacs
Difference between bulk laxatives & osmotic laxatives?
Bulk take a long time to work whereas osmotic laxative work in a couple hours
