Gastric Physiology 4/12/23 Flashcards
4 Key cell types in Stomach
Mucous
Parietal
Chief cells
Enterendocrine cells
What cells secrete Gastric acid?
Parietal cells
What type of acid is Gastric acid?
Hydrochloric acid
How are H+ ions taken out of Parietal cells?
Via active transport
What type of stimulation turns on Gastric acid secretion in the Cephalic stage?
Parasympathetic
Which Neurotransmitter is released during Stimulation of Gastric acid secretin during the cephalic phase?
Acetylcholine
What causes the Cephalic phase of Gastric acid secretion to begin?
Sight, Smell and taste of food
Chewing
What two things does Acetylcholine do in the cephalic phase?
Acts directly on parietal cells
ACh triggers release of gastrin and histamine
Second phase of Gastric acid secretion name?
Gastric phase
How much HCl does the average human produce per day
2 litres/day
What is released during the Gastric phase?
Gastrin
What does the release of Gastrin trigger to be released?
Histamine
What does Protein in the stomach trigger the release of?
Gastrin
How does increased proteins in the Lumen cause more parietal cell activity?
Acts as a buffer, mops up H+ ions
Decreases secretion of somatostatin
What is Somatostatin?
Protein that reduces Gastrin secretion
What causes Gastric acid secretion to turn off in the Gastric Phase?
Low luminal pH
What causes gastric acid secretion to turn off in the intestinal phase (4)
Duodenal distension
Low luminal pH
Presence of Amino acids and fatty acids
What is released in the intestinal phase?
Enterogastrones