What does hypoxia refer to?

Hypoxia specifically refers to a condition in which there is a reduction of oxygen availability at the tissue level. This means that despite blood flow potentially being normal, the tissues themselves are not receiving adequate oxygen to meet their metabolic needs. This can be due to various factors, such as respiratory issues, decreased oxygen levels in the blood, or conditions affecting the ability of hemoglobin to release oxygen to the tissues.

Understanding hypoxia is crucial in pathophysiology, as it can lead to cellular dysfunction and even necrosis if not addressed promptly. The other options describe different physiological conditions that are not indicative of hypoxia itself, such as hypercapnia (excessive CO2), ischemia (lack of blood flow), and hyperoxia (excess oxygen).