One type of metabolic feedback loop that influences weight control involves the regulation of glucose levels in the blood. Which organ in the digestive system participates in this regulation by breaking down glycogen

Explanation:

1. Glucagon: it control the glucose levels in the blood.  

2. Glucagon is produced by the alpha cells, in the pancreas.

3. It prevent  dropping of  blood glucose levels too low. so, it acts on the liver in many ways:

4. It stimulates the breakdown of glycogen which is stored in the liver  into glucose, which  finally  released into the bloodstream, this process is known as glycogenolysis.

5. It  also stimulates  the production of glucose from amino acid molecules and some other non carbohydrate pre-cursors, by the process known as gluconeogenesis.