In the human body this is called homeostasis and it involves a number of methods.
An example of one is when you are outside on a rather warm day. Your body will attempt to keep you core body temperature
between 98°F (37°C) and 100°F (37.8°C).
When your temperature increases, your body activates a system to promote heat loss. This returns body temperature back to normal.
When your brain receives a temperature warning from your body,
it sends signals to various organs and body systems, which try to slow heat production.
This is what begin to happen:
•Sweating: Sweating is one of the first methods your body will use to control your temperature.
Sweat cools your skin as it evaporates. This helps lower your internal temperature.
•Vasodilatation: Your CNS may instruct the capillaries under the surface of your skin to dilate, or open and increases blood flow at the skin surface.
These let your body release heat through radiation.