ering oxygen to the tissues, 3) the efficiency of the respiratory enzymes within the cells to transfer hydrogen to molecular oxygen (Grollman, 1978). A deficiency in any of these areas can result in the body cells not having an adequate supply of oxygen. It is this inadequate supply of oxygen that results in difficulties for the body at higher elevations. ANOXIA A lack of sufficient oxygen in the cells is called anoxia. Sometimes the term hypoxia, meaning less oxygen, is used to indicate an oxygen debt. While anoxia literally means "no oxygen" it is often used interchangeably with hypoxia. There are different types of anoxia based on the cause of the oxygen deficiency. Anoxic anoxia refers to defective oxygenation of the blood in the lungs. This is the type of oxygen deficiency that is of concern when ascending to greater altitudes with a subsequent decreased partial pressure of O2. Other types of oxygen deficiencies include: anemic anoxia (failure of the blood to transport adequate quantities of oxygen), stagnant anoxia (the slowing of the circulatory system), and histotoxic anoxia (the failure of respiratory enzymes to adequately function). Anoxia can occur temporarily during normal respiratory system regulation of changing cellular needs. An example of this would be climbing a flight of stairs. The increased oxygendemand of the cells in providing the mechanical energy required to climb ultimately produces a local hypoxia in the muscle cell. The first noticeable response to this external stress is usually an increase in breathing rate. This is called increased alveolar ventilation. The rate of our breathing is determined by the need for O2 in the cells and is the first response to hypoxic conditions. BODY RESPONSE TO ANOXIA If increases in the rate of alveolar respiration are insufficient to supply the oxygen needs of the cells the respiratory system responds by general vasodilation. This allows a greater flow o...
