Gas exchange

Gas exchange

The process by which oxygen is extracted from inhaled air into the bloodstream, and, at the same time, carbon dioxide is eliminated from the blood and exhaled.

Mentioned in: Respiratory Failure

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gas

any elastic aeriform fluid in which the molecules are widely separated from each other and so have free paths.

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alveolar gas

the gas in the alveoli of the lungs, where gaseous exchange with the capillary blood takes place. See also oxygen, carbon dioxide.

blood gas

see blood gas analysis.

gas bubble disease

a disease of fish in tanks in which the water is supersaturated with oxygen or nitrogen. Gas embolism develops in the gills. Air bubbles can be seen in the gills, eyes and under the skin and the fish show bizarre nervous behavior.

gas cap

a cap of gas above fluid or solid contents in a hollow viscus, e.g. in a static rumen. Seen radiologically in distended intestinal loops in paralytical ileus.

gas edema disease

see blue wing disease.

gas exchange

gases move by simple diffusion in response to pressure differences; net diffusion occurs from areas of high pressure to areas of lower pressure irrespective of whether the gas is present as a gas or in solution or gases moving from gas to solution or vice versa. The rate of exchange of gases in body tissues, e.g. between alveolar space and erythrocyte, is influenced by many other factors, especially the diffusion distance and the solubility of the gas.

gas inhalation

irritant gases, e.g. manure gas, cause pulmonary edema.

laughing gas

nitrous oxide.

manure gas poisoning

see manure pit gas poisoning.

tear gas

a gas that produces severe lacrimation by irritating the conjunctivae. See lacrimator.

gas transport

relates to the efficiency of transport of gas, e.g. oxygen, by the patient as a whole. The efficiency of gas transport varies widely between normal individuals and between species, e.g. athletic breeds of horses and dogs have much faster gas transport systems than human athletes; the efficiency of gas transport in the individual depends largely on the rapidity of increase in minute ventilation, plus a similar rate of increase in cardiac output.

gas tube

see crookes' tube.