What defines hypoxic hypoxia?

Hypoxic hypoxia refers specifically to a condition where there is insufficient oxygen available for the body to function, particularly in the bloodstream. This situation commonly occurs at high altitudes, where the partial pressure of oxygen decreases, leading to less available oxygen for the body to utilize.

In hypoxic hypoxia, the primary issue is the low levels of oxygen in the environment affecting the oxygen concentration in the blood. This means that, regardless of the functioning of the circulatory system, the body does not receive adequate oxygen to maintain normal physiological functions. The focus here is on the availability of oxygen rather than its ability to be transported or utilized by tissues, making this option the most accurate representation of hypoxic hypoxia.

Understanding this, it's important to recognize that the other options refer to different types of hypoxia or physiological issues. For example, if blood cannot transport oxygen or if tissues can't utilize it, the issue would pertain to different forms of hypoxia, such as stagnant or histotoxic hypoxia.