Energy
Energy balance is the homeostasis of energy in living systems. It is measured with the following equation:
Energy intake = internal heat produced + external work + storage.
When calculating energy balances in the body, energy is often measured in calories, with the definitions of a calorie falling into two classes:
- The small calorie or gram calorie (symbol: cal) approximates the energy needed to increase the temperature of 1 gram of water by 1 °C. This is about 4.2 joules.
- The large calorie, kilogram calorie, dietary calorie or food calorie (symbol: Cal) approximates the energy needed to increase the temperature of 1 kilogram of water by 1 °C. This is exactly 1,000 small calories or about 4.2 kilojoules.
Read more about this topic: Human Homeostasis
Famous quotes containing the word energy:
“The very presence of guilt, let alone its tenacity, implies imbalance: Something, we suspect, is getting more of our energy than warrants, at the expense of something else, we suspect, that deserves more of our energy than we’re giving.”
—Melinda M. Marshall (20th century)
“Reckoned physiologically, everything ugly weakens and afflicts man. It recalls decay, danger, impotence; he actually suffers a loss of energy in its presence. The effect of the ugly can be measured with a dynamometer. Whenever man feels in any way depressed, he senses the proximity of something “ugly.” His feeling of power, his will to power, his courage, his pride—they decline with the ugly, they increase with the beautiful.”
—Friedrich Nietzsche (1844–1900)
“The chief function of the city is to convert power into form, energy into culture, dead matter into the living symbols of art, biological reproduction into social creativity.”
—Lewis Mumford (1895–1990)