There are 2 stages in the complex process of homeostasis
Firstly, sensory cells or receptors detect a change in temperature and/or chemical composition within the body. This change in the environment is known as a stimulus.
Secondly, effector organs (muscles or glands) the work to reverse/counteract the change; this is known as a response if it is successful in reversing the effect of the stimulus – it should return the body to homeostasis.
All organisms have a set point – which is an ideal value for a variable (temperature). Homeostasis does not maintain the variable at the exact set point; homeostasis is still maintained so long as there is not a large fluctuation from the set point. If the fluctuation is larger than the normal range a negative feedback mechanism is activated – it is termed negative , as it responds to the change in the environment.