Feedback mechanism:

A mechanism or a signal that tends to initiate (or accelerate) or to inhibit (or slow down) a process.

Supplement

An example of positive feedback loop is the onset of contractions in childbirth. When contraction begins, the hormone oxytocin is released into the body to stimulate further contractions. As for the negative feedback loop, an example is the regulation of blood glucose levels. If blood glucose levels continue to rise it may result in diabetes. In fact, there are many biologic processes that use negative feedback to maintain homeostasis or dynamic equilibrium.

Possitive Feedback Mechanism:

A feedback mechanism resulting in the amplification or growth of the output signal.

Example:

One example of biological positive feedback is at the onset of contractions in childbirth. When contraction occurs, oxytocin is released into the body stimulating more contractions. Thus, the result is an increased amplitude and frequency of contractions.

Negative Feed back Mechanism:

A feedback in which the system responds in an opposite direction to the perturbation.

Example:

It is a self-regulatory system in which it feeds back to the input a part of a system’s output so as to reverse the direction of change of the output.

The process reduces the output of a system in order to stabilize or re-establish internal equilibrium. There are several negative feedback in biological system to regulate and maintain homeostasis. Some of which are the regulation of hormone synthesis, blood glucose levels, body temperature, and baroflex in blood pressure.