Metabolism at the Max: How Vertebrate Organisms Respond to Physical Activity

摘要: Activity metabolism is supported by phosphorylated reserves (adenosine triphosphate, creatine phosphate), glycolytic, and aerobic metabolism. Because there no apparent variation between vertebrate groups in or glycolytic potential of skeletal muscle, maximal metabolic rate major represents selection operating on mechanisms. Maximal rates oxygen consumption vertebrates are increased conductive diffusive fluxes from the environment to mitochondria. CO2 efflux mitochondria must be matched flux, imbalances pH will occur. Among vertebrates, a variety modes locomotion vastly different cardiorespiratory architectures. However, interclass comparisons strongly implicate systemic transport as rate-limiting step for all groups. The key evolutionary that accounts approximately 10-fold increase flux endotherms versus ectotherms appears heart rate. Other variables such ventilation, pulmonary/gill, tissue diffusing capacity, have excess capacity thus not limiting consumption. During activity, ratio ventilation respiratory system blood flow remarkably similar among extraction efficiency increases while decreases, suggesting provides largest resistance flux. Despite large activity metabolism, appear limited cardiovascular systems, respectively.