How does homeostasis work to control temperature in the body? (high temperature example)

Homeostasis works as a negative feedback mechanism meaning when a certain factor goes too high or too low the body will work to reverse it and bring it back to normal i.e. if temperature goes too high then the body will have a negative response to decrease the temperature and bring it back to normal, so that enzymes can work at their optimum temperature (37 degrees celsius). If the thermoreceptors in the blood detect that the body's core temperature - not surface temperature - is too high then it will send a signal to the hypothalamus in the brain: this is the body's regulatory centre.

The hypothalamus will then send a signal via the sympathetic nervous system - the system that causes something to be 'switched on' to create the response - to the skin and a number of responses will happen such as:

• Sweating: the signal instructs the sweat glands to produce more sweat and lose heat by evaporation off of the skin surface

• Vasodilation: the signal instructs the arterioles near the surface of the skin to open up (dilate) which directs the blood flow to capillaries near the skin surface where heat can be radiated away

• Pilorelaxation: the nerve impulse causes the erector pili muscles to relax causing the hairs on the body to lay flat which means less air is trapped between the hairs and the skin, reducing insulation