Lecture 26: Pharmacology and physiology of gastric acid secretion Flashcards
What is the function of parietal cell in the stomach?
Parietal cells secrete large volume of HCL into stomach
What is gastric acid secretion stimulated by?
secretion initiated by good in the stomach
Reflex stimulation of enteric nerves
G cells directly responsive to foodstuffs
What is the function of the mucus barrier in the stomach?
Mucus is secreted by surface mucous epithelial cells, it generates a continuous alkaline mucus barrier and protects stomach lining from acid and pepsin.
Paritetal cell acid secretion is stimulated by?
Acetylcholine from nerves acting on M3 receptors.
Stimulated by parasympathetic activity (vagus) in response to food sight, smell, taste
Histamine from enterocharmaffin like cells acting from H2 receptors.
Gastrin from G cells in the gastric epithelium
What is gastric acid secretion inhibited by?
Somatostatin from endocrine epithelial cells, they response to stomach acid levels (negative feedback pathway)
What is gastric acid neutralised by?
Food in stomach and the somatostatin release falls.
What is peptic Ulcer?
Ulceration of the stomach or duodenum, very common and significant cause of death.
What is H. pylori?
most peptic ulcers are caused by bacteria (H.pylori) they enter the body through contamination and they damage the mucus layer as they grow there, allowing the stomach acid to reach the stomach or duodenum
What are the causes of peptic ulcer?
H.pylori bacteria
NSAIDs i.e. aspirin and ibuprofen (these drugs reduce the production of mucus)
Smoking
Stress
What are the symptoms of peptic ulcer?
Heartburn, abdominal pain, bloating Nausea and vomiting MELENA bloody vomit peritonitis
What is GORD/GERD
Gastro oesophageal Reflux disease
Symptoms of GORD?
Heartburn, acid reflux, oespohagitis
bloating, bleching
nausea,
Pain when swallowing
Treatment for H. pylori
Combination of antibacterial therapy plus PPI (proton pump inhibitor)
to eliminate helicobacter and decrease acid secretion.
Treatment of peptic ulcers, what are cytoprotective drugs?
They enhance mucosal barrier and they increase viscosity and tenacity of mucus.
For example; surcalfate (AL(OH)3/ sulfated sucrose complex
How does sucralfate work?
releases aluminium in acid to leave negatively charged complex, they bind to glycoproteins which decrease mucus degradation.
