Artificial gills are unproven conceptualised devices to allow a human to be able to take in

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

from surrounding water. This is speculative technology that has not been demonstrated in a documented fashion. Natural

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s work because nearly all animals with gills are thermoconformers (cold-blooded), so they need much less oxygen than a

thermoregulator Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

(warm-blood) of the same size.Why don't people have gills?
As a practical matter, it is unclear that a usable artificial gill could be created because of the large amount of oxygen a human would need extracted from the water.

Methods

Several potential methods exist for the development of artificial gills. One proposed method is the use of

liquid breathing Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid (such as a perfluorocarbon), rather than breathing air. By selecting a liquid that is capable of holding large amounts of oxy ...

with a

membrane oxygenator A membrane oxygenator is a device used to add oxygen to, and remove carbon dioxide from the blood. It can be used in two principal modes: to imitate the function of the lungs in cardiopulmonary bypass (CPB), and to oxygenate blood in longer term ...

to solve the problem of

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

retention, the major limiting factor in liquid breathing. It is thought that a system such as this would allow for diving without risk of

decompression sickness Decompression sickness (abbreviated DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompressio ...

. They are generally thought to be unwieldy and bulky, because of the massive amount of water that would have to be processed to extract enough oxygen to supply an active diver, as an alternative to a

scuba set A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. ''Scuba'' is an anacronym for self-contained underwater breathin ...

. An average diver with a fully closed-circuit

rebreather A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's breathing, exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. ...

needs 1.5 liters of oxygen per minute while swimming or 0.64 liter per minute while resting. At least of sea water per minute would have to be passed through the system, and this system would not work in

anoxic The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of diss ...

water. Seawater in tropical regions with abundant plant life contains of oxygen per liter of water.Fundamentals of Environmental Measurement
/ref> These calculations are based on the dissolved oxygen content of water.

References

External links

* History of attempts to develop artificial gills and the principles and problems involved. * *
'Like A Fish' Underwater Breathing System: Artificial Gills for U.S. Navy SEALs?

Artificial gills in fiction
(called a "hydrolung") in ''

Tom Swift Tom Swift is the main character of six series of American juvenile science fiction and adventure novels that emphasize science, invention, and technology. First published in 1910, the series totals more than 100 volumes. The character was ...

and the Electronic Hydrolung'', by Victor Appleton. It is a

, fitted with a device that extracts oxygen from surrounding water. {{DEFAULTSORT:Artificial Gills (Human) Diving medicine Underwater breathing apparatus Membrane technology

Methods

See also

References

External links