Copyright © Philip M. Parker, INSEAD. Terms of Use.
Definition: Homeostasis |
HomeostasisNoun1. Metabolic equilibrium actively maintained by several complex biological mechanisms that operate via the autonomic nervous system to offset disrupting changes. Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. |
| Domain | Definition |
Health | The processes whereby the internal environment of an organism tends to remain balanced and stable. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
Homeostasis in layman's terms means balance or equilibrium. It is the property of an open system to regulate its internal environment so as to maintain a stable condition, by means of multiple dynamic equilibrium adjustments controlled by interrelated regulation mechanisms. The term was coined in 1932 by Walter Cannon from two Greek words (to remain the same). The term usually is used in the sense of biological homeostasis in humans and animals.
Ecological, biological, and social systems are homeostatic. They oppose change to maintain equilibrium. If the system does not succeed in reestablishing its balance, it will be in a state where constraints are more severe than before. This can ultimately lead to the destruction of the system if the disturbances persist.
Complex systems, such as a human body, must have homeostasis to maintain stability and to survive. These systems do not only have to endure to survive; they must adapt themselves and evolve to modifications of the environment and it must evolve.
Homeostatic systems show several properties
A frequent paradox for those responsible for the maintenance and evolution of a complex system (be it a body, an ecosystem, a state, or a planet) is how can a stable organization whose goal is to maintain itself and endure, be able to change and evolve?
- they are ultrastable;
- their whole organisation, internal, structural, and functional, contributes to the maintenance of equilibrium
- they are unpredictable (the resulting effect of a precise action often has the oppposite effect to what was expected)
Feedback
When a change of variable is occurring, there are many types of feedback with which the system to react.Negative feedback is a reaction in which the system responds in such a way as to reverse the direction of change. Since this tends to keep things constant, it allows the maintenance of homeostasis. For instance, when the concentration of carbon dioxide in the human body increases, the lungs are signalled to increase their activity and expel more carbon dioxide.
In positive feedback, the response is to amplify the change in the variable. This has a de-stabilizing effect, so does not result in homeostasis. Positive feedback is less common in naturally occurring systems than negative feedback, but it has its applications. For example, in nerves, a threshold electric potential triggers the generation of a much larger action potential. (See also leverage points.)
Ecological homeostasis
In the Gaia hypothesis, James Lovelock stated that the entire mass of living matter on Earth (or any planet with life) functions as a vast organism that actively modifies its planet to produce the environment that suits its needs. In this view, the entire planet maintains homeostasis. Whether this sort of system is present on Earth is still open to debate. However, some relatively simple homeostatic mechanisms are generally accepted. For example, when atmospheric carbon dioxide levels rise, plants are able to grow better and thus remove more carbon dioxide from the atmosphere.
Biological homeostasis
Homeostasis is one of the fundamental characteristics of living things. It is the maintenance of the internal environment within tolerable limits.With regard to any parameter, an organism may be a conformer or a regulator. Regulators try to maintain the parameter at a constant level, regardless of what is happening in its environment. Conformers allow the environment to determine the parameter. For instance, endothermic animals maintain a constant body temperature, while ectothermic animals exhibit wide variation in body temperature.
This is not to say that conformers may not have behavioral adaptations that allow them to exert some control over the parameter in question. For instance, reptiles often sit on sun-heated rocks in the morning to raise their body temperatures.
An advantage of homeostatic regulation is that it allows the organism to function more effectively. For instance, ectotherms tend to become sluggish at low temperatures, whereas endotherms are as active as always. On the other hand, regulation reqires energy. One reason why snakes can eat only once a week is that they use much less energy for maintaining homeostasis.
Homeostasis in the human body
All sorts of factors affect the suitability of our body fluids to sustain life; these include properties like temperature, salinity, acidity (carbon dioxide), and the concentrations of nutrients and wastes (urea, glucose, various ion, oxygen). Since these properties affect the chemical reactions that keep bodies alive, there are built-in physiological mechanisms to maintain them at desirable levels.
This control is achieved with various organs in the body. For example:
Most of these organs are controlled by hormones secreted from the pituitary gland, which in turn is directed by the hypothalamus.
- Thermal regulation
- The skeletal muscles can shiver to produce heat if the body temperature is too low.
- Non-shivering thermogenesis involves the decomposition of fat to produce heat.
- Sweating cools the body with the use of evaporation.
- Chemical regulation
- The pancreas produces insulin and glucagon to control blood-sugar concentration.
- The lungs take in oxygen and give off carbon dioxide.
- The kidneys remove urea, and adjust the concentrations of water and a wide variety of ions.
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Homeostasis."
Crosswords: Homeostasis |
| English words defined with "homeostasis": homeostatic. (references) |
| Specialty definitions using "homeostasis": Bone Remodeling ♦ Receptors, Calcitonin, Receptors, Parathyroid Hormone ♦ Solitary Nucleus. (references) |
| Domain | Title |
Books |
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Source: compiled by the editor from various references; see credits. | |
| Subject | Topic | Quote |
Health | Pregnancy represents a significant physiological stress on maternal skeletal homeostasis. (references) | |
At the biologic level, there is variability in the regulation of homeostasis, organ system reserve, immunologic responsiveness, and body composition. (references) | ||
With the loss of homeostasis, water rushes into the cell making it swell (called cytotoxic edema) until the cell membrane bursts under the internal pressure. (references) | ||
Source: compiled by the editor from ICON Group International, Inc.; see credits. | ||
| "Homeostasis" is generally used as a noun (singular) -- approximately 100.00% of the time. "Homeostasis" is used about 21 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted) |
| Parts of Speech | Percent | Usage per 100 Million Words | Rank in English |
| Noun (singular) | 100% | 21 | 76,261 |
Source: compiled by the editor from several corpora; see credits.
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Language | Translations for "homeostasis"; alternative meanings/domain in parentheses. | |
Danish | homoeostase. (various references) | |
Dutch | homeostase. (various references) | |
Finnish | homeostaasi. (various references) | |
French | homéostasie, homéostase. (various references) | |
German | Homeostasie, Homöostase, Homöostase. (various references) | |
Greek | ομοιόσταση, ομοιοστασία. (various references) | |
Italian | omeostasi (steady state). (various references) | |
Japanese Kanji | 恒常性 (constancy). (various references) | |
Japanese Katakana | こうじょうせい (constancy). (various references) | |
Korean | 항상성. (various references) | |
Pig Latin | omeostasishay.(various references) | |
Portuguese | homeostase. (various references) | |
Spanish | homeostasis, homeostasia. (various references) | |
| Source: compiled by the editor from various translation references. | ||
Misspellings | |
"Homeostasis" is suggested in spellcheckers for the following: hemeostasis, homeastasis, homeoestasis, homeostases, homeostasus, homeostasys, homeostatis, homestasis, homiostasis, homostasis. (additional references) | |
| Source: compiled by the editor, based on several corpora (additional references). | |
| # of Phoneme Matches | Pronunciation | Word(s) rhyming with "homeostasis" (pronounced hō'mēōstā"sus) |
| 4 | -ā" s u s | glacis. |
| 3 | -s u s | acidosis, amniocentesis, analysis, antithesis, apotheosis, archdiocese, arteriosclerosis, atherosclerosis, axis, catharsis, census, cirrhosis, colossus, consensus, crisis, diagnosis, dialysis, diocese, electrolysis, fibrosis, Genesis, geotaxis, heterosis, hydrolysis, hypnosis, hypothesis, meiosis, metamorphosis, misdiagnosis, morphogenesis, Narcissus, necrosis, nemesis, nephrosis, neurofibromatosis, neurosis, nexus, organogenesis, photosynthesis, phototaxis, plexus, preadolescence, proboscis, prognosis, prosthesis, psoriasis, psychoanalysis, psychokinesis, psychosis, rhesus, sclerosis, symbiosis, synopsis, synthesis, Tarsus, telexes, Texas, thesis, thrombosis, tuberculosis, urinalysis, versus. |
Source: compiled by the editor (additional references); see credits. | ||
Scrabble® Enable2K-Verified Anagrams | |
| Words within the letters "a-e-h-i-m-o-o-s-s-s-t" | |
-1 letter: hemostasis. | |
-2 letters: maestosos, smoothies. | |
-3 letters: amitoses, amosites, atheisms, atomises, maestoso, massiest, messiahs, misseats, mossiest, osteomas, osteosis, ostomies, smoothes, smoothie. | |
-4 letters: amosite, ashiest, atheism, atomies, atomise, homiest, hostess, mashies, messiah, miseats, misseat, missets, mitoses, osmoses, osmosis, osteoma, ostoses, ostosis, samites, shamois, siestas, smashes, smooths, somites, soothes, stashes, tamises, tassies, theisms. | |
-5 letters: assets, assist, hastes, heists, hisses. | |
| Words containing the letters "a-e-h-i-m-o-o-s-s-s-t" | |
+3 letters: histoplasmoses. | |
+4 letters: schistosomiases, schoolmasterish. | |
| Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro. | |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
