Homeostasis
<p ><b>Homeostasis</b> (from <a href="http://en.wikipedia.org/wiki/List_of_Greek_words_with_English_derivatives" title="List of Greek words with English derivatives" >Greek</a>: ὅμοιος, <i>hómoios</i>, "similar"<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-0" >[1]</a></sup>, and στάσις, <i>stásis</i>, "standing still"<sup id="cite_ref-1" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-1" >[2]</a></sup>) is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties such as temperature or <a href="http://en.wikipedia.org/wiki/PH" title="PH" >pH</a>. It can be either an <a href="http://en.wikipedia.org/wiki/Open_system_(systems_theory)" title="Open system (systems theory)" >open</a> or <a href="http://en.wikipedia.org/wiki/Closed_system" title="Closed system" >closed</a> system.</p>
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It was defined by <a href="http://en.wikipedia.org/wiki/Claude_Bernard" title="Claude Bernard" >Claude Bernard</a> and later by <a href="http://en.wikipedia.org/wiki/Walter_Bradford_Cannon" title="Walter Bradford Cannon" >Walter Bradford Cannon</a> in 1926,<sup id="cite_ref-2" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-2" >[3]</a></sup> 1929<sup id="cite_ref-3" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-3" >[4]</a></sup> and 1932.<sup id="cite_ref-4" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-4" >[5]</a></sup><sup id="cite_ref-5" class="reference" ><a href="http://en.wikipedia.org/wiki/Homeostasis#cite_note-5" >[6]</a></sup>
Typically used to refer to a living <a href="http://en.wikipedia.org/wiki/Organism" title="Organism" >organism</a>, the concept came from that of <a href="http://en.wikipedia.org/wiki/Milieu_int%C3%A9rieur" title="Milieu intérieur" >milieu intérieur</a> that was created by <a href="http://en.wikipedia.org/wiki/Claude_Bernard" title="Claude Bernard" >Claude Bernard</a> and published in 1865. Multiple dynamic equilibrium adjustment and regulation mechanisms make homeostasis possible.</p>