Homeostasis in a general sense refers to stability, balance or equilibrium. Maintaining a stable internal environment requires constant monitoring and adjustments as conditions change. This adjusting of physiological systems within the body is called homeostatic regulation.
Parts or Mechanism
Homeostatic regulation involves three parts or mechanisms: 1) the receptor, 2) the control center and 3) the effector. The receptor receives information that something in the environment is changing. The control center or integration center receives and processes information from the receptor. And lastly, the effector responds to the commands of the control center by either opposing or enhancing the stimulus. A metaphor to help us understand this process is the operation of a thermostat. The thermostat monitors and controls room temperature. The thermostat is set at a certain temperature that is considered ideal, the set point. The function of the thermostat is to keep the temperature in the room within a few degrees of the set point. If the room is colder than the set point, the thermostat receives information from the thermometer (the receptor) that it is too cold. The effectors within the thermostat then will turn on the heat to warm up the room. When the room temperature reaches the set point, the receptor receives the information, and the thermostat "tells" the heater to turn off. This also works when it is too hot in the room. The thermostat receives the information and turns on the air conditioner.