Describe homoeostasis using temperature control as an example.

Homeostasis is the maintenance of a constant internal environment. The body tends to use a series of negative feedback loops to allow this. Using temperature as an example, the body likes to maintain a core temperature of 37°C. The hypothalamus in the brain is the main centre for control if this. If there is a change, such as a rise in temperature, it is detected and then the hypothalamus will initiate several processes. One is for sweat glands to increase their activity. The more sweat that evaporated from the skin, the cooler the body becomes. A second process is to dilate blood vessels. This allows increased heat loss via the skin, and explains why you can redden when warm. Finally, there is a behavioural control, as you would take of a layer if you are hot, rather than putting on an extra jumper. These allows you to correct the initial rise in temperature, and the opposite would occur if the temperature had fallen, as well as the nervous system signalling involuntary muscle contractions, aka shivering.