Facilitated Oxygen Transport

Abstract

The amount of dioxygen an organism needs for aerobic metabolism depends on many factors, size and activity being the most important. However, as an approximate figure, we may say that a typical higher eukaryote will utilize about 3.5 ml dioxygen kg−1 body weight per minute. This must reach the tissues where active metabolism is occurring and be maintained there at a steady-state pressure of approximately 2 Torr. This will assure a sufficient rate of delivery to mitochondria and allow continued utilization therein for oxidative reactions (see Chap. 4). The problem faced by the organism is how to assure sufficient delivery to all the tissues, even those buried deep in the body, sometimes while inhabiting an oxygen-poor environment. There are a number of possible strategies to solve this problem. All have been used at one time or another in the course of evolution.