When we first meet Dory, she's just swimming around minding her own business when suddenly she bumps into Marlin and instantly offers to help him hunt down his son.
Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability internationally. Alveolar hypoxia and consequent hypoxemia increase in prevalence as disease severity increases.
Hypoxic hypoxia can be caused by inadequate breathing as well as other causes. Anemic hypoxia -- In the setting of anemia, low hemoglobin levels result in a reduced ability of the blood to carry oxygen that is breathed in, and hence, a diminished supply of oxygen available to the tissues.