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:
“Much of the modern resistance to chastity comes from men’s belief that they “own” their bodies—those vast and perilous estates, pulsating with the energy that made the worlds, in which they find themselves without their consent and from which they are ejected at the pleasure of Another!”
—C.S. (Clive Staples)
“The persons who constitute the natural aristocracy, are not found in the actual aristocracy, or, only on its edge; as the chemical energy of the spectrum is found to be greatest just outside of the spectrum.”
—Ralph Waldo Emerson (1803–1882)
“The flattering, if arbitrary, label, First Lady of the Theatre, takes its toll. The demands are great, not only in energy but eventually in dramatic focus. It is difficult, if not impossible, for a star to occupy an inch of space without bursting seams, cramping everyone else’s style and unbalancing a play. No matter how self-effacing a famous player may be, he makes an entrance as a casual neighbor and the audience interest shifts to the house next door.”
—Helen Hayes (1900–1993)