What is a positive feedback loop? How does it work?
A positive feedback loop attempts to increase a deviation from a set parameter when it occurs.
A receptor detects the deviation and notifies a control centre, which creates a response activating an effector. The effect takes an action that will intensify the deviation. A limiting factor will eventually cease the loop or the system will collapse.
Eg. When the skin is cut, chemicals are released that activate platelets. The platelets begin to clot the wound, releasing chemicals when they activate, this is the start of the positive feedback loop. These chemicals stimulate more platelets, which release more chemical when activated, creating a cycle. The cycle stops when the bleeding stops and the platelets cannot activate (limiting factor).
Other examples: Breastfeeding, giving birth.