Homeostatic Là Gì

Emeritus Professor Kelvin Rodolfo of the University of Illinois at Chicago"s Department of Earth and Environmental Sciences provides this answer


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Homeostasis, from the Greek words for "same" & "steady," refers to any process that living things use to lớn actively maintain fairly stable conditions necessary for survival. The term was coined in 1930 by the physician Walter Cannon. His book, The Wisdom of the Body, describes how the human body maintains steady levels of temperature & other vital conditions such as the water, salt, sugar, protein, fat, calcium và oxygen contents of the blood. Similar processes dynamically maintain steady-state conditions in the Earth"s environment.

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Homeostasis has found useful applications in the social sciences. It refers to how a person under conflicting stresses and motivations can maintain a stable psychological condition. A society homeostatically maintains its stability despite competing political, economic & cultural factors. A good example is the law of supply và dem&, whereby the interaction of supply and demvà keeps market prices reasonably stable.

Homeostatic ideas are shared by the science of cybernetics (from the Greek for "steersman"), defined in 1948 by the mathematician Norbert Wiener as "the entire field of control and communication theory, whether in the machine or in the animal." Cybernetic systems can "remember" disturbances và thus are used in computer science to store và transmit information. Negative sầu feedbaông xã is a central homeostatic & cybernetic concept, referring to lớn how an organism or system automatically opposes any change imposed upon it.


For example, the human body uses a number of processes to lớn control its temperature, keeping it cthua kém khổng lồ an average value or norm of 98.6 degrees Fahrenheit. One of the most obvious physical responses khổng lồ overheating is sweating, which cools the body by making more moisture on the skin available for evaporation. On the other hvà, the body reduces heat-loss in cold surroundings by sweating less and reducing blood circulation khổng lồ the skin. Thus, any change that either raises or lowers the normal temperature automatically triggers a counteracting, opposite or negative sầu feedbachồng . Here, negative merely means opposite, not bad; in fact, it operates for our well being in this example. Positive sầu feedbaông chồng is a response lớn change from the normal condition that increases the departure even more.

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For example, if a person"s temperature is raised lớn about 107 degrees Fahrenheit, the negative feedback systems stop operating. A person with a high fever has hot, dry skin if they bởi vì sweat khổng lồ help cool it. Not only have sầu the negative sầu feedbaông chồng systems shut down in such a case; the increased temperature speeds up the body toàn thân chemistry, which causes the temperature to rise even more, which in turn speeds up the toàn thân chemistry even more, và so forth. This vicious cycle of positive feedbaông chồng, a "runaway" process, can only over in death if not stopped.

It is important khổng lồ emphasize that homeostatic reactions are inevitable and automatic if the system is functioning properly, and that a steady state or homeostasis may be maintained by many systems operating together. For example, flushing is another of the body"s automatic responses to lớn heating: the skin reddens because its small blood vessels automatically exp& to bring more heated blood cthất bại to the surface where it can cool. Shivering is another response khổng lồ chilling: the involuntary movements burn toàn thân tissue lớn produce more body toàn thân heat.

Negative feedbachồng arises out of balances between forces and factors that mutually influence each other. To illustrate several of its important characteristics, we can regard a car và its driver as a unified, complex, homeostatic or "goal-seeking" system--a cyborg, or "cybernetic organism," in that it seeks lớn keep the oto moving on traông chồng. The driver does not steer by holding the wheel in a fixed position but keeps turning the wheel slightly lớn the left và right, seeking the wheel positions that will bring the naturally meandering oto baông chồng on trachồng. Disturbance, or departure from equilibrium, is every bit as important as negative sầu feedback: Systems cannot correct themselves if they bởi not stray.

Oscillation is a common and necessary behavior of many systems. If the oto skids, the driver automatically responds by quickly steering in the opposite direction. Such abrupt negative sầu feedbaông xã, however, usually over-corrects, causing the oto to lớn move sầu toward the other side of the road. A negative feedbaông xã, if it is as large as the disturbance that triggered it, may become an impressed change in the direction opposite to that of the original disturbance. The car và driver recovers from the skid by weaving from side to side, swerving a little less each time. In other words, each feedbaông chồng is less than the last departure from the goal, so the oscillations "damp out." Negative sầu feedbaông xã takes time and such a time lag is an essential feature of many natural systems. This may set the system lớn oscillating above sầu và below the equilibrium cấp độ.