Gastric juice production is regulated by both the autonomic nervous system and hormones. The parasympathetic nervous system and hormone gastrin stimulate parietal cells to produce gastric acid, acting directly on the cells and indirectly by stimulating the secretion of histamine from ECL cells. Gastric acid production is tightly regulated by positive regulators like histamine release and negative feedback mechanisms. Four cell types are involved: parietal cells, G cells that secrete gastrin, D cells that secrete somatostatin, and ECL cells.

1. How is gastric juice production
regulated.

2. • PHASES OF ACID SECRETION — The physiologic
stimulation of acid secretion has classically been
divided into three interrelated phases: cephalic,
gastric, and intestinal [2].
• The cephalic phase is activated by the thought, taste,
smell and site of food, and swallowing. It is mediated
mostly by cholinergic/vagal mechanisms.
• The gastric phase is due to the chemical effects of
food and distension of the stomach. Gastrin appears
to be the major mediator since the response to food
is largely inhibited by immunoneutralizing or
blocking gastrin action at its receptors.

3. Composition of gastric juice
• 1/ mucus
• 2/ HCl
• 3/ pepsinogen

4. • Gastric acid production is regulated by both
the autonomic nervous system and several
hormones.

5. • The parasympathetic nervous system, via the
vagus nerve, and the hormone gastrin
stimulate the parietal cell to produce gastric
acid.

6. • They directly act on parietal cells and
indirectly, through the stimulation of the
secretion of the hormone histamine from
enterochromaffine-like cells (ECL).

7. • The production of gastric acid in the stomach
is tightly regulated by positive regulators and
negative feedback mechanisms.

8. Four types of cells are involved in this
process:
parietal cells,
• G cells,
• D cells
• enterochromaffine-like cells.
• Besides this, the endings of the vagus nerve
(CN X) and the
• intramural nervous plexus in the digestive
tract influence the secretion significantly.

9. Nerve endings in the stomach
• Nerve endings in the stomach secrete two
stimulatory neurotransmitters
• 1/ acetylcholine
• 2/ gastrin-releasing peptide.

10. • Their action is both direct on parietal cells and
mediated through the secretion of gastrin
from G cells and histamine from
enterochromaffine-like cells.

11. Gastrin
• Gastrin acts on parietal cells directly and
indirectly too, by stimulating the release of
histamine.

12. positive regulation mechanism
• The release of histamine is the most
important positive regulation mechanism of
the secretion of gastric acid in the stomach

15. • Release of histamine by gastrin from
enterochrommafin-like cells (ECL, in green)
appears to be the major physiologic mechanism
by which gastrin stimulates acid secretion,
although parietal cells (in blue) also have gastrin
receptors. In addition, the ECL cells integrate
stimulatory messages from cholinergic nerves
and inhibition by locally released somatostatin.