What does hypoxia refer to?

Hypoxia refers specifically to low oxygen levels in the tissues of the body. This condition can occur due to various reasons, such as respiratory diseases, high altitude, or circulatory issues, leading to inadequate oxygen supply to cells and tissues. When tissues are hypoxic, they cannot perform their metabolic functions effectively, which can result in cellular injury or death if the condition persists.

The other choices describe different physiological states; for instance, increased blood flow to tissues usually refers to hyperemia, not hypoxia. High blood pressure in the arteries is known as hypertension, a separate condition that does not directly relate to oxygen levels. A mass occluding blood flow refers to an obstruction, which can lead to ischemia but is not synonymous with hypoxia itself. Thus, understanding that hypoxia is specifically about insufficient oxygen at the tissue level is crucial in pathophysiology.