Hypoxia and cellular injury

Hypoxia refers to the failure of tissues to get an adequate oxygen supply. Hypoxia can be caused for many reasons, but the main type where there is a lack of oxygen in the arterial blood is called hypoxic hypoxia. Oxygen tension in the lungs and the arterial blood is lowered preventing the hemoglobin to saturate to its normal level. This will have impacts on all parts of the body. Hypoxic hypoxia can be attributed to low tensions of oxygen in the inhaled air, especially at high altitudes and through breathing in of inert gases and anesthetic agents. Lung problems such as asthma and pneumonia leave you with a higher chance of forming this hypoxia. Overall, any shallow movements of respiration from any source, that decrease rate or amplitude could potentially cause hypoxic hypoxia. Shallow habitual breathing could possibly cause hypoxic hypoxia like effects. 

Hypoxia and hypoxemia are often used interchangebly although the former is a condition in which the supply of oxygen is insufficient for normal life while the latter is a condition where there is a low arterial oxygen. Symptoms may be acute or chronic and vary in intensity from mild to severe: shortness of breath, rapid breathing, mouth breathing, drooling, fast heart rate, inability to communicate, confusion and even death. Treatment may include oxygen by face mask or nasal cannula, mechanical ventilation, hyperbaric chamber, or other devices or medicines to open airways. Prevention strategies include avoidance of circumstances that reduce oxygen in the environments or by providing oxygen before symptoms develop.

Bodies of water carry dissolved oxygen for the healthy survival and reproduction of aquatic life. When oxygen concentration in water is healthy, aquatic life is healthy. When oxygen concentartion of water is low, pollution results killing off aquatic life. Our bodies behave in similar manner. Our breathing oxygenate our blood which circulates all over our body supplying oxygen to each oneof the almost 40 trillion living cells inside of it. When the oygen concentation of our blood is too low, our cells cannot survive and reproduce in a healthy way. Our personal hypoxia pollutes our bodies killing off our cells just like aquatic hypoxia pollutes bodies of water and killing off aquatic life.

Note that hypoxia can be system wide or localized due to inequality in the supply of oxygen for some reason or another. 

References:
Cafaro, Ross P. "Hypoxia: Its Causes and Symptoms." Journal of the American Dental Society of Anesthesiology 7, no. 4 (1960): 4-8.
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