What type of hypoxia is caused by the reduction of PO2 in the lungs?

Hypoxic hypoxia occurs when there is insufficient oxygen available for the body or a specific part of the body, primarily due to low partial pressure of oxygen (PO2) in the lungs. This type of hypoxia directly relates to the atmospheric conditions or altitude that lead to reduced oxygen pressure, making it difficult for the bloodstream to absorb adequate amounts of oxygen.

In environments where the atmosphere has a lower oxygen content, such as high altitudes, the lungs may not be able to deliver enough oxygen to the bloodstream, resulting in hypoxic hypoxia. This condition affects overall oxygen delivery to tissues, leading to symptoms such as shortness of breath and fatigue.

Stagnant hypoxia, on the other hand, results from inadequate blood flow, histotoxic hypoxia involves the inability of cells to utilize oxygen despite having a normal supply, and hyperoxic hypoxia refers to excess oxygen levels that can also be harmful. Each of these different types of hypoxia has distinct causes and mechanisms that do not focus primarily on the reduction of PO2 in the lungs as seen in hypoxic hypoxia.