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Human thermoregulation. 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 ...
Physical law relating heat loss to temperature difference. In the study of heat transfer, Newton's law of cooling is a physical law which states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment. The law is frequently qualified to include the condition that ...
The process of heat transfer from one place to another place without the movement of particles is called conduction, such as when placing a hand on a cold glass of water—heat is conducted from the warm skin to the cold glass, but if the hand is held a few inches from the glass, little conduction would occur since air is a poor conductor of heat.
The resting human body generates about two-thirds of its heat through metabolism in internal organs in the thorax and abdomen, as well as in the brain. The brain generates about 16% of the total heat produced by the body. [8] Heat loss is a major threat to smaller creatures, as they have a larger ratio of surface area to volume.
The basal metabolic rate accounts for about 70% of the daily calorie expenditure by individuals. It is influenced by several factors. In humans, BMR typically declines by 1–2% per decade after age 20, mostly due to loss of fat-free mass, [3] although the variability between individuals is high. [4]
Thermoregulation. 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.
It may also occur from any condition that decreases heat production or increases heat loss. [1] Commonly, this includes alcohol intoxication but may also include low blood sugar, anorexia and advanced age. [2] [1] Body temperature is usually maintained near a constant level of 36.5–37.5 °C (97.7–99.5 °F) through thermoregulation. [2]
Sensible heat. Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system, and some macroscopic variables of the body or system, but leaves unchanged certain other macroscopic variables of the body or system, such as volume or pressure. [1][2][3][4]