Factors Determining Total Body and Hind Limb Oxygen Consumption in Normal and Shocked Dogs
O2 uptake is determined by the relative contributions of O2 transport (=blood flow × art.O2 content) and O2 extraction. At constant metabolic rate variations in O2 transport produce inverse changes in O2 extraction (Fig.1),and with changes in metabolic rate the resulting variations in O2 extraction produce a feedback response of the autoregulatory flow system (1). In addition to cellular metabolism, O2 extraction is also determined by the contractile state of the precapillary sphincters (2): the inverse variations in O2 extraction with changes in blood pressure (3) ana arterial pCO2 (4) (Fig.1) are presumably related to this function. In order to quantify these complex interactions we submitted these parameters to multiple regression analysis with O2 uptake as the dependent variable.
KeywordsLimb Blood Flow Inverse Change Total Body Oxygen Body Oxygen Consumption Precapillary Sphincter
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