### element | oxygen:

Atmospheric oxygen
* Most atmospheric oxygen is of biological origin.
* colors our world by oxidizing minerals and scattering our sun s rays.
* diffuses through the water-air interface.

Atomic oxygen
* consists of only one oxygen atom, and is rare in the lower atmosphere.
* is difficult to produce on Earth, yet is readily available on orbit.
* produces a yellow-green color, and at extremely high altitudes a red color.

Excess oxygen
* Most excess oxygen needs for growth.
* is inhibitory - establishment of a host parasite relationship.

Free oxygen
* combines with iron ores and other minerals quickly unless replenished.
* critical factor in determining what organisms live in certain aquatic habitats.
* is added back by the chemical process during combustion
  - released

### element | oxygen:

Hyperbaric oxygen
* acts as a drug
  - an alpha-adrenergic drug
* appears to reduce mortality and morbidity.
* can produce a variety of effects in addition to reducing air and gas embolism
  - noticeable toxic effects if administered incorrectly
* improves wound healing in normal and ischemic skin tissue.
* introduces very high levels of oxygen into body tissues.
* is oxygen delivered at above atmospheric pressure
  - simply intermittent, high-dose oxygen inhalation therapy
  - unproven
* means oxygen under higher than normal pressure.
* reduces the indirect component of injury by preventing such activation
  - vischemla-induced skeletal muscle Injury
* works well along with topical peroxide gel or peroxide sits baths.

### element | oxygen:

Low oxygen
* can cause fish kills
  - kill fish
* causes vasoconstriction in the alveolar capillaries.
* occurs during stroke or heart attack.
+ Sickle-cell disease, The disease: Diseases :: Genetic disorders :: Blood
  * This is a life-long disease. It starts in childhood. The red blood cells take up an abnormal, rigid, sickle shape. The cells also become sticky. This causes difficult blood flow when cells flow through long narrow capillaries. Low oxygen increases the problem. As they pass through low oxygen areas most cells take up this shape. The cells then stick to the inner wall of blood vessels, especially the branching point of veins. This leads to a blockade of blood flow in many organs. Severe complications may result.

Molecular oxygen
* acts as the final electron acceptor.
* has two unpaired electrons and common radical.
* is also a co-substrate in the reaction
  - the other substrate and the second oxygen atom ends up in water
  - vital for generation of energy that in turn is fundamental to life
* thermodynamically powerful yet kinetically slow oxidant.
* weighs kg, while helium weighs kg.

Oxygen demand
* increases as temperature and time of reaction increases.
* is prior to heat and vapor exchange.

Oxygen therapy
* Oxygen therapies are extremely controversial
  - have many therapeutic uses with beneficial effects on every part of the body
* can assist with the growth and development in children with chronic lung conditions.

Oxygen toxicity
* can cause seizures.
* has three chief manifestations.
* is in part related to production of free radicals and induced membrane damage
  - the limiting factor when diving with nitrox

Reactive oxygen
* is related to both, the arrest of growth and the start of cell differentiation.
* species production and role in kidney.

Supplemental oxygen
* can be important and life-saving for individuals with low blood oxygen levels.
* critical step in treating a severe or life-threatening illness or injury.
* helps to prevent complications from hypoxia.
* is available for use during exercise when requested by a physician
  - the most commonly prescribed drug in hospitals
* reduces the incidence of postoperative nausea and vomiting.