Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers

In 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 wi...

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Autores principales:	GÜNTHER,BRUNO, MORGADO,ENRIQUE, JIMÉNEZ,RAÚL F
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2003
Materias:	Dimensional analysis Biological similarities Allometric equations Rest and exercise Hemorrhagic shock Integral feedback
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000200011
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spelling	oai:scielo:S0716-976020030002000112003-11-19Homeostasis and Heterostasis: from Invariant to Dimensionless NumbersGÜNTHER,BRUNOMORGADO,ENRIQUEJIMÉNEZ,RAÚL F Dimensional analysis Biological similarities Allometric equations Rest and exercise Hemorrhagic shock Integral feedback In 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.info:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.36 n.2 20032003-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000200011en10.4067/S0716-97602003000200011
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Dimensional analysis Biological similarities Allometric equations Rest and exercise Hemorrhagic shock Integral feedback
spellingShingle	Dimensional analysis Biological similarities Allometric equations Rest and exercise Hemorrhagic shock Integral feedback GÜNTHER,BRUNO MORGADO,ENRIQUE JIMÉNEZ,RAÚL F Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
description	In 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.
author	GÜNTHER,BRUNO MORGADO,ENRIQUE JIMÉNEZ,RAÚL F
author_facet	GÜNTHER,BRUNO MORGADO,ENRIQUE JIMÉNEZ,RAÚL F
author_sort	GÜNTHER,BRUNO
title	Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
title_short	Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
title_full	Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
title_fullStr	Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
title_full_unstemmed	Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers
title_sort	homeostasis and heterostasis: from invariant to dimensionless numbers
publisher	Sociedad de Biología de Chile
publishDate	2003
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000200011
work_keys_str_mv	AT guntherbruno homeostasisandheterostasisfrominvarianttodimensionlessnumbers AT morgadoenrique homeostasisandheterostasisfrominvarianttodimensionlessnumbers AT jimenezraulf homeostasisandheterostasisfrominvarianttodimensionlessnumbers
_version_	1718441353437773824

Homeostasis and Heterostasis: from Invariant to Dimensionless Numbers

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