Biology AQA Past Paper (2015) - Unit 03 (Higher). Describe how the brain monitors body temperature.

The hypothalamus is the processing centre in the brain that controls body temperature (constant temperature of 37ºC approx.). It triggers changes to effectors, such as sweat glands and muscles controlling body hair. For instance, hairs on the skin trap more warmth if they are standing up, and less if they are lying flat. Tiny muscles in the skin control this in order to gain or release heat. Similarly, when humans sweat, they segregate chemicals (such as water) that by evaporation help to reduce body temperature. Without these mechanisms, humans would constantly suffer from heat strokes (body becomes too hot); and hypothermia (body becomes too cold).