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Ventilation facilitates respiration. Respiration refers to the utilization of oxygen and balancing of carbon dioxide by the body as a whole, or by individual cells in cellular respiration. [1] The most important function of breathing is the supplying of oxygen to the body and balancing of the carbon dioxide levels.
Pressure as a function of the height above the sea level. The human body can perform best at sea level, [7] where the atmospheric pressure is 101,325 Pa or 1013.25 millibars (or 1 atm, by definition). The concentration of oxygen (O 2) in sea-level air is 20.9%, so the partial pressure of O 2 (pO 2) is 21.136 kilopascals (158.
In the region from sea level to around 3,000 m (10,000 ft), known as the physiological-efficient zone, oxygen levels are usually high enough for humans to function without supplemental oxygen and altitude decompression sickness is rare. The physiological-deficient zone extends from 3,600 m (12,000 ft) to about 15,000 m (50,000 ft).
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 gasses including CO 2, further diluting the oxygen concentration and lowering the PO 2.
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. The rest of the difference is due to the continual uptake of oxygen by the pulmonary capillaries , and the continual diffusion of CO 2 out of the capillaries ...
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas. Other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines ...
Air quality in Los Angeles was at "moderate" levels on Thursday morning, as judged by the EPA's Air Quality Index rating system. Moderate air quality is between 51 and 100, or in the yellow band ...
The process of breathing does not fill the alveoli with atmospheric air during each inhalation (about 350 ml per breath), but the inhaled air is carefully diluted and thoroughly mixed with a large volume of gas (about 2.5 liters in adult humans) known as the functional residual capacity which remains in the lungs after each exhalation, and ...