ABSTRACT
Living organisms obtain energy for their biological processes by the oxidation of complex chemical foodstus to simpler compounds, usually with the eventual formation of carbon dioxide, water and other waste products. Oxygen, therefore, is essential for the maintenance of continued aerobic respiration and normal function by living material. Normoxia describes the state in which a physiologically adequate supply of oxygen to the tissues, whether in quantity or molecular concentration, is available. When the level of oxygen available is below that requirement, a state of hypoxia is said to exist. Humans are extremely sensitive and vulnerable to the eects of deprivation of oxygen, and severe hypoxia nearly always results in a rapid deterioration of most bodily functions; eventually, it will lead to death. Hypoxaemia is a general term meaning a deciency in the oxygenation of the blood, but it is not synonymous with the term tissue hypoxia, which may arise from one or more causes.
