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Real-time magnetic resonance imaging of the human thorax during breathing X-ray video of a female American alligator while breathing. Breathing (spiration [1] or ventilation) is the rhythmical process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.
The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used. The oxygen cycle is the biogeochemical cycle of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. [1]
Oxygen flows from areas with high partial pressure of oxygen (PO 2, also known as oxygen tension) to areas of lower PO 2. Air is typically around 21% oxygen, and at sea level, the PO 2 of air is typically around 159 mmHg. [2] Humidity dilutes the concentration of oxygen in air. As air is inhaled into the lungs, it mixes with water and exhaust ...
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]
This rise in oxygen concentration, known as the Neoproterozoic oxygenation event or "Second Great Oxygenation Event", was likely caused by the evolution of nitrogen fixation in cyanobacteria and the rise of eukaryotic photoautotrophs (green and red algae), and often cited as a possible contributor to later large-scale evolutionary radiations ...
The alveolar oxygen partial pressure is lower than the atmospheric O 2 partial pressure for two reasons. Firstly, as the air enters the lungs, it is humidified by the upper airway and thus the partial pressure of water vapour (47 mmHg) reduces the oxygen partial pressure to about 150 mmHg.
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A nitrogen generator Bottle of 4Å molecular sieves. Pressure swing adsorption provides separation of oxygen or nitrogen from air without liquefaction. The process operates around ambient temperature; a zeolite (molecular sponge) is exposed to high pressure air, then the air is released and an adsorbed film of the desired gas is released.