A regulatory mechanism in the body of an organism that helps to maintain homeostasis by modifying the value of one or more variables so they stay near their set points regardless of outside conditions. An example would be body temperature. If, for instance, a person goes into the cold, the body maintains its normal temperature by changing its processes in various ways. For example, tiny blood vessels, called capillaries, very near the surface of the skin will constrict so blood does not come near the outside and radiate all of its heat. By all of these various mechanisms, If temperature increases too much, the person could experience adverse effects. Therefore, once a certain level of temperature is detected, the mechanisms producing or conserving heat are sensitive to this and shut down. Once the body cools to a certain point, the mechanisms take effect again. Negative feedback loops are by far the most common way the body maintains homeostasis. Most negative feedback loops have three components, the receptor which monitors the variable (in our example, body temperature), a control center (in our example this would be what determines the set point, the brain), and the effector(s), which are responsible for changing the values of the variable. A related term is positive feeback loop.