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One form of homeostasis is thermoregulation. Body temperature varies in every individual, but the average internal temperature is 37.0 °C (98.6 °F). [1] Sufficient stress from extreme external temperature may cause injury or death if it exceeds the ability of the body to thermoregulate.
As in other mammals, human thermoregulation is an important aspect of homeostasis. In thermoregulation, body heat is generated mostly in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. [1] Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid.
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation.
The best-known homeostatic mechanisms in humans and other mammals are regulators that keep the composition of the extracellular fluid (or the "internal environment") constant, especially with regard to the temperature, pH, osmolality, and the concentrations of sodium, potassium, glucose, carbon dioxide, and oxygen.
Environmental conditions, primarily temperature and humidity, affect the ability of the mammalian body to thermoregulate. The psychrometric temperature, of which the wet-bulb temperature is the main component, largely limits thermoregulation. It was thought that a wet-bulb temperature of about 35 °C (95 °F) was the highest sustained value ...
The only known living homeotherms are mammals and birds, as well as one lizard, the Argentine black and white tegu. Some extinct reptiles such as ichthyosaurs, pterosaurs, plesiosaurs and some non-avian dinosaurs are believed to have been homeotherms. Tachymetabolism [c] maintains a high "resting" metabolism. In essence, tachymetabolic ...
The honey bee, for example, does so by contracting antagonistic flight muscles without moving its wings (see insect thermoregulation). [18] [19] [20] This form of thermogenesis is, however, only efficient above a certain temperature threshold, and below about 9–14 °C (48–57 °F), the honey bee reverts to ectothermy. [19] [20] [21]
On the other side, the mechanisms for thermoregulation did not evolve separately, but rather in connection with other functions. [19] These mechanisms were more likely quantitative rather than qualitative and it involved selection of appropriate habitats, changes in levels of locomotor activity, optimum energy liberation, and conservation of ...