Gastric Actions

Question 1

What is the primary function of the stomach?

Answer 1

Storage (up to 2-4 litres max)

Question 2

What are the main cell types in the stomach?

And what protective compounds are present?

Answer 2

Within the gastric pits:
Chief cells - pepsinogen
Parietal cells - acid production (few near the antrum)
ECL cell - histamine release (help stimulate acid production)
G cell - gastrin release (AA initiates, stimulates acid production, most near antrum)
D cell - somatostatin release (high acid initiates, stops acid production)
Columnar epithelium - migrate out of the pits to repair damaged mucosa

On the surface/top of gastric pits:
Foveolar (mucus) cells - alkaline mucus production
Columnar epithelium - the superior surface is resistant to acid (the lateral and basal surfaces are vulnerable)

Protective compounds:
Gastric surfactant layer on top of the mucosa - repels ionic charges from getting to the mucosa (alcohol acts as a surfactant and ruins the mucosal barrier)
Mucin - mucus
High vascularity - hyperaemic (lots of blood) during damage,means quick repair