Saturday, January 16, 2010

Explain negative feedback control of body temperature?

using thermoreceptors, the hypothalamus, %26amp; the temperature control center.Explain negative feedback control of body temperature?
The relatively constant conditions within organisms, or the physiological processes by which such conditions are maintained in the face of external variation.





Similar homeostatic controls are used to keep factors such as temperature and blood pressure nearly constant despite changes in an organism's activity level or surroundings. Such systems operate by detecting changes in the variable that the system is designed to hold constant and initiating some action that offsets any change. All incorporate a sensor within the system that responds when the actual condition differs from the desired one, a device to ensure that any action taken will reduce the difference between actual and desired, and an effector to take the needed action as directed. The crucial aspect is that information is fed back from effector to sensor and action is taken to reduce any imbalance—hence the term negative feedback.


Body temperature in mammals is regulated by a sensor that consists of cells within the hypothalamus of the brain. Several effectors are involved, which vary among animals. These include increasing heat production through nonspecific muscle activity such as shivering; increasing heat loss through sweating, panting, and opening more blood vessels in the skin (vasodilation); and decreasing heat loss through thickening of fur (piloerection) and curling up. Humans sweat, but they retain only a vestige of piloerection (“goose flesh”).





While the homeostatic mechanisms described involve the neural and endocrine systems of mammals, it is clear that such arrangements pervade systems from genes to biological communities, and that they are used by the simplest and the most complex organisms.

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