Describe the functions of the gastric secretions.

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College Answer

Candidates were expected to list and briefly define the role of the various substances
produced and secreted by the stomach. These included the hormones gastrin and
somatostatin, the enzymes pepsin, lipase and gelatinase, the electrolytes Na+, K+ and HCO3-
, HCl and water, prostaglandins and mucus, and intrinsic factor.
For example: HCl secreted by parietal cells to produce a very acidic environment pH 1-3.5.
This optimizes proteolytic activity of pepsin, has a direct proteolytic role, aids ferric iron
conversion to the more soluble ferrous ion, and is important for bactericidal activity and
innate immunity. It also stimulates pancreatic and biliary secretions.
Good answers divided the functions into digestive, hormonal, mucosal protection, immunity
etc. Marks were not gained for mention of the secretions of other GIT organs.
SyllabusQ12b
Reference: Guyton and Hall 11th edition p791-799