How Our Body Controls Temperature

The hypothalamus is the processing centre in the brain that controls body temperature.
It does this by triggering changes to effectors, such as sweat glands and muscles controlling body hair. Heat stroke can happen when the body becomes too hot; and hypothermia when the body becomes too cold.
Temperature control
Temperature control is the process of keeping the body at a constant temperature of 37°C.
Sweat is made up mostly of water but also contains minerals, urea, lactic acid, ammonia and sugar. Sweating is your body’s way of keeping body temperature at the norm of 37°C. When you run long distances or exercise in hot weather, for example, your muscles exert themselves and your body overheats. Sweating is your body’s way of bringing your temperature back to normal.
How our body maintains a constant temperature
Temperature receptors in the skin detect changes in the external temperature of the body. They pass this information to the processing centre in the brain, called the hypothalamus.
The processing centre also has temperature receptors to detect changes in the temperature of the blood. The processing centre automatically triggers changes to the effectors to ensure our body temperature remains constant, at 37°C.
The effectors are sweat glands and muscles.
If we are too hot or too cold, the processing centre sends nerve impulses to the skin, which has two ways to either increase or decrease heat loss from the body's surface.
Blood and temperature control - Higher
When we are too hot, blood vessels supplying blood to the skin can swell or dilate (vasodilation). This allows more warm blood to flow near the surface of the skin, where the heat can be lost to the air.
This is why some people's skin looks redder when they feel too hot.
When we are too cold the blood vessels supplying warm blood to the skin become narrow or constrict (vasoconstriction). This