Enteral respiration, also referred to as cloacal respiration or intestinal respiration, is a form of
respiration
Respiration may refer to:
Biology
* Cellular respiration, the process in which nutrients are converted into useful energy in a cell
** Anaerobic respiration, cellular respiration without oxygen
** Maintenance respiration, the amount of cellula ...
in which gas exchange occurs in the posterior cavity of the
enteral system. This is used in various species as an accessory respiration mechanism in hypoxic environments as a means to supplement blood oxygen.
Turtles
![Turtle Cloacal Respiration](https://upload.wikimedia.org/wikipedia/commons/d/d8/Turtle_Cloacal_Respiration.png)
Some
turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
s, especially those specialized in diving, are highly reliant on
cloacal
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, an ...
respiration
Respiration may refer to:
Biology
* Cellular respiration, the process in which nutrients are converted into useful energy in a cell
** Anaerobic respiration, cellular respiration without oxygen
** Maintenance respiration, the amount of cellula ...
during dives. They accomplish this by having a pair of accessory air bladders connected to the cloaca which can absorb oxygen from the water.
Other animals
Various
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
, as well as
polychaete
Polychaeta () is a paraphyletic class (biology), class of generally marine invertebrate, marine annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that ...
worms and even
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s, are specialized to take advantage of the constant flow of water through the cloacal respiratory tree of
sea cucumbers
Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothuria ...
while simultaneously gaining the protection of living within the sea cucumber itself. At night, many of these species emerge from the anus of the sea cucumber in search of food.
The
pond loach
The pond loach (''Misgurnus anguillicaudatus''), also known as the Dojo loach or oriental weatherfish, is a freshwater fish in the loach family Cobitidae. They are native to East Asia but are also popular as an aquarium fish and introduced else ...
is able to respond to the periodic drying in their native habitats by burrowing into the mud and exchanging gas through the posterior end of their alimentary canal.
Studies have shown that mammals are capable of performing intestinal respiration to a limited degree in a laboratory setting. Mice were subjected to hypoxic conditions and supplied oxygen through their intestines survived an average of 18 minutes compared to 11 minutes in the control group. When the intestinal lining was abraded before oxygen was introduced, most of the animals survived for at least 50 minutes. Investigations are planned regarding the effectiveness of the strategy, the safety of this application of perfluorocarbons, and the feasibility of application to humans.
See also
*
Cutaneous respiration Cutaneous respiration, or cutaneous gas exchange (sometimes called, skin breathing), is a form of respiration in which gas exchange occurs across the skin or outer integument of an organism rather than gills or lungs. Cutaneous respiration may be th ...
References
{{Reflist
Respiration
Animal anatomy
Digestive system