Question

Why is digestion considered positive feedback and not negative?

Answer 1

The digestion system actually has both positive and negative feedback loops

Explanation:

An example of a negative feedback loop iun the digestive system, for example, occurs when the low pH of the stomach inhibits gastrin secretion by the G cells which results in less acid secretion. If the pH becomes raised, gastrin production is no longer inhibited which thus allows acid to be secreted until the desired pH is reached.

A positive feedback loop occurs when peptides cause acid and pepsinogen to be released and this in turn causes more peptides in the stomach, which causes acid and pepsinogen to be released, as a way of aiding digestion when eating.

Adapted from http://digestiveteam.tripod.com/id4.html