Homeostasis can be defined as the body's tendency to maintain a stable equilibrium between the physiological processes. Any changes in the body is detected by the various receptors present in various regions of the body.
The receptor send the signals to the processing or control centres present in the brain. in these processing centres, the changes are noticed, and accordingly the signals are generated. These signal are carried through the effector neuron, which generates the final response.
Hence, the homeostatic regulation usually involves a receptor that detects a particular stimulus, and a control center that responds to the stimulus by communicating with an effector neuron whose activity has an effect on the same stimulus.