Lecture 11: Stomach (Sanchez) Flashcards
Why is it normal to have backflow into the stomach from the duodenum in horses?
They have a loose pylorus
Where do most gastric mucosa secretions occur?
fundic part of stomach
What is secreted from cardiac part of stomach?
mucuous, bicarb.
What is secreted from fundic part of stomach?
pepsin, lipase, somatostatin, histamine, HCl
What is secreted from pyloric part of stomach?
pepsin, lipase, somatostatin, gastrin
gastric glands can be comprised of many types of cells including:
mucus surface cells, mucus neck cells, enterochromaffin-like cells, parietal cells, chief cell, D cells
D cells produce:
somatostatin
ECL cells produce:
histamine
parietal cells produce:
HCl
chief cells produce:
pepsinogen, gastric lipase
G cells produce:
gastrin
Parietal cells have receptors for:
- Ach
- gastrin
- histamine (most important)
ECL cells have receptors for:
Ach, gastrin
Major mech. of secretion for parietal cells
via H/K ATPase. On the basolateral surface of the cell, Na/K, Na/H, and HCO3/Cl exchangers get K and Cl into the cell so K can be exchanged for H by H/K ATPase, ultimately allowing the free H and Cl to combine and form HCl.
What stimulates G cells?
Ach, amino acids in gastric lumen, gastric distension
What inhibits G cells?
somatostatin
What stimulates D cells?
acidic lumen (lower than pH 4)
T or F: horses are continuous acid secreters
T
Do ECL secretions (histamine) have a paracrine or endocrine effect?
paracrine
Do G cell secretions (gastrin) have a paracrine or endocrine effect?
endocrine
What stimulates ECL cells?
Ach, gastrin
What inhibits ECL cells?
somatostatin
Main stimulators of acid secretion
1) amino acids
2) protein
3) gastric distension
4) Helicobacter pylori bacteria
Main inhibitors of acid secretion
1) luminal acid
2) lower than pH 4 gastric pH
