What condition occurs when there is a lack of oxygen in body tissues?

The condition characterized by a lack of oxygen in body tissues is known as hypoxia. This occurs when there is insufficient oxygen available for tissues to function effectively, which can lead to cellular damage and impaired metabolic processes. Hypoxia can arise from various sources, such as high altitudes, respiratory illnesses, or inadequate blood circulation.

In contrast, hyperoxia refers to an excess of oxygen in the tissues, which is the opposite condition. Ischemia involves a restriction of blood flow to the tissues, resulting in reduced oxygen supply, but it is a broader term that doesn't specifically define the oxygen deficiency itself. Apoxia, while somewhat similar, is not a commonly used term in medical contexts and generally refers to a complete lack of oxygen, which is a more severe condition than hypoxia. Thus, hypoxia is the most accurate and widely used term to describe a lack of oxygen in body tissues.