Describe the measures the body takes to achieve homeostasis in response to temperature changes

The body is able to utilise a number of measures in order to maintain an optimum body temperature of around 37 degrees celsius. Firstly, capillaries close to the skin surface are able to vasodilate (expand) in response to high temperatures using molecules such as Nitric Oxide. This dilation means more heat is able to be lost through the skin as more blood, containing heat, is brought close to the surface. Equally, blood vessels can vasoconstrict (narrow) in response to cold in order to conserve heat. Sweating is another action taken in response to high temperatures, sweat glands secrete a salty solution containing mostly water which, once at the surface, can evaporate and take heat with it. Thirdly, lower temperatures stimulate the action of shivering - repeated muscle contraction which generates heat as a by-product of this greater metabolic rate. In addition to this, 'goosebumps' are formed as erector pili muscles next to hair follicles contract - hairs stand on end, trapping an insulating layer of heat. Finally, behavioral changes also occur - such as wearing more clothes in colder conditions, or fewer clothes in warmer conditions.