Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Allometric scaling of the maximum metabolic rate of mammals: oxygen transport from the lungs to the heart is a limiting step | Theoretical Biology and Medical Modelling BioMed Central Research Open Access Allometric scaling of the maximum metabolic rate of mammals oxygen transport from the lungs to the heart is a limiting step Page R Painter Address Office of Environmental Health Hazard Assessment California Environmental Protection Agency P. O. Box 4010 Sacramento California 95812 USA Email Page R Painter - ppainter@ Corresponding author Published II August 2005 Received 22 March 2005 Theoretical Biology and Medical Modelling 2005 2 3 1 doi 1742-4682-2-31 Accepted 11 August 2005 This article is available from http content 2 1 31 2005 Painter licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background The maximum metabolic rate MMR of mammals is approximately proportional to M0-9 where M is the mammal s body weight. Therefore MMR increases with body weight faster than does the basal metabolic rate BMR which is approximately proportional to M0-7. MMR is strongly associated with the capacity of the cardiovascular system to deliver blood to capillaries in the systemic circulation but properties of this vascular system have not produced an explanation for the scaling of MMR. Results Here we focus on the pulmonary circulation where resistance to blood flow impedance places a limit on the rate that blood can be pumped through the lungs before pulmonary edema occurs. The maximum pressure gradient that does not produce edema determines the maximum rate that blood can flow through the pulmonary veins without compromising the diffusing capacity of oxygen. We show that modeling the pulmonary venous tree as a fractal-like vascular network leads to a scaling equation for maximum cardiac output that predicts MMR as a .
