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dc.creatorGÜNTHER,BRUNO
dc.creatorMORGADO,ENRIQUE
dc.creatorJIMÉNEZ,RAÚL F
dc.date2003-01-01
dc.date.accessioned2019-05-02T21:21:10Z
dc.date.available2019-05-02T21:21:10Z
dc.identifierhttps://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000200011
dc.identifier.urihttp://revistaschilenas.uchile.cl/handle/2250/81466
dc.descriptionIn the present paper we have examined the applicability of dimensionless and invariant numbers (DN & IN) to the analysis of the cardiovascular system of mammals, whose functions were measured at standard metabolic conditions. The calculated IN did not change when we compared these figures with those obtained in dogs while they were submitted to graded exercise on a treadmill. In both instances, rest and exercise, the constancy of the IN prevailed, in accordance with Cannon's principle of "homeostasis" (1929). On the contrary, when dogs were examined during a standardized hypovolemic shock, we observed a breakdown of the IN, and the resulting DN evolved as a reliable index of the condition of "heterostasis" as defined by H. Selye. The robustness of the homeostatic regulations is based on high-gain integral feedback mechanisms, while "heterostasis" could be associated with low-gain integral feedback processes, when organisms are submitted to unitary step disturbances or to changes of the set-point at the entrance of the feedback loop.
dc.formattext/html
dc.languageen
dc.publisherSociedad de Biología de Chile
dc.relation10.4067/S0716-97602003000200011
dc.rightsinfo:eu-repo/semantics/openAccess
dc.sourceBiological Research v.36 n.2 2003
dc.subjectDimensional analysis
dc.subjectBiological similarities
dc.subjectAllometric equations
dc.subjectRest and exercise
dc.subjectHemorrhagic shock
dc.subjectIntegral feedback
dc.titleHomeostasis and Heterostasis: from Invariant to Dimensionless Numbers


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