Thermoregulation 1, Enzymes need to work

Life can only exist within narrow temperature ranges. Some animals, e.g. fish and reptiles, vary their body temperature depending on environmental conditions. These animals are described as ‘cold blooded’ or poikilothermic. However, in higher animals and humans, body temperature must be finely controlled within a fairly narrow temperature range. As previously discussed, cellular biochemistry is essential for life. All intracellular biochemistry is catalysed by enzymes which only work within narrow ranges of temperature. If the body becomes too hot or too cold enzymic activity will be reduced and physiological functions will no longer work efficiently. Eventually both hyper or hypothermia will lead to death. Humans are biologically classified as homoiothermes because we maintain a constant body temperature. This means that if body temperature starts to rise cooling mechanisms must be employed. Likewise, when body temperature falls there must be mechanisms available to conserve heat and increase body temperature.