How the Body Controls Temperature
The hypothalamus of the brain (a small cherry sized part of the brain found on the underside in the middle) senses the temperature of the blood.
If the blood is too warm then it will set about the mechanisms which cool the body. This continues until the blood is the correct temperature when the hypothalamus will switch off the cooling mechanisms. If the blood is too cold then the mechanisms which conserve heat and warm the body are started, stopping when the blood temperature reaches normal. This mechanism of switching off the warming/cooling systems when the body reaches the correct temperature is called negative feedback.
Although the average body temperature is 37°C the body temperature actually fluctuates a great deal. The body is constantly triggering the mechanisms which warm the body and cool the body in an attempt to keep it within the acceptable limits.
