This article provides an overview of the journey of inspired oxygen after its uptake across the alveolar–capillary interface, and the interplay among tissue perfusion, diffusion, and cellular respiration in the transport and utilization of oxygen. The critical interactions between oxygen and its facilitative carriers (hemoglobin in red blood cells and myoglobin in muscle cells), and with other respiratory and vasoactive molecules (carbon dioxide, nitric oxide, and carbon monoxide), are emphasized to illustrate how this versatile system dynamically optimizes regional convective transport and diffusive gas exchange. The rates of reciprocal gas exchange in the lung and the periphery must be well-matched and sufficient for meeting the range of energy demands from rest to maximal stress but not excessive as to become toxic. The mobile red blood cells play a vital role in matching tissue perfusion and gas exchange by dynamically regulating the controlled uptake of oxygen and communicating regional metabolic signals across different organs. Intracellular oxygen diffusion and facilitation via myoglobin into the mitochondria, and utilization via electron transport chain and oxidative phosphorylation, are summarized. Physiological and pathophysiological adaptations are briefly described. Dysfunction of any component across this integrated system affects all other components and elicits corresponding structural and functional adaptation aimed at matching the capacities across the entire system and restoring equilibrium under normal and pathological conditions.

本文概述了吸入氧穿过肺泡-毛细血管界面后的旅程，以及组织灌注、扩散和细胞呼吸在氧气运输和利用中的相互作用。强调氧气及其辅助载体（红细胞中的血红蛋白和肌肉细胞中的肌红蛋白）之间以及与其他呼吸和血管活性分子（二氧化碳、一氧化氮和一氧化碳）之间的关键相互作用，以说明这种多功能系统如何动态地优化区域对流传输和扩散气体交换。肺和外周气体相互交换的速率必须良好匹配，并且足以满足从休息到最大压力的能量需求范围，但又不能过多以致产生毒性。移动的红细胞通过动态调节受控的氧气吸收和在不同器官之间传递区域代谢信号，在匹配组织灌注和气体交换方面发挥着至关重要的作用。总结了细胞内氧通过肌红蛋白扩散和促进进入线粒体，以及通过电子传递链和氧化磷酸化的利用。简要描述了生理和病理生理适应。该集成系统中任何组件的功能障碍都会影响所有其他组件，并引发相应的结构和功能适应，旨在匹配整个系统的能力并恢复正常和病理条件下的平衡。